Durable anti-reflective articles

ABSTRACT

Embodiments of durable, anti-reflective articles are described. In one or more embodiments, the article includes a substrate and an anti-reflective coating disposed on the major surface. The article exhibits an average light transmittance of about 94% or greater over an optical wavelength regime and/or an average light reflectance of about 2% or less over the optical wavelength regime, as measured from an anti-reflective surface. In some embodiments, the article exhibits a maximum hardness of about 8 GPa or greater as measured by a Berkovich Indenter Hardness Test along an indentation depth of about 50 nm or greater and a b* value, in reflectance, in the range from about −5 to about 1 as measured on the anti-reflective surface only at all incidence illumination angles in the range from about 0 degrees to about 60 degrees under an International Commission on Illumination illuminant.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority under 35 U.S.C. §119 ofU.S. Provisional Application Ser. No. 62/098,836 filed Dec. 31, 2014,U.S. Provisional Application Ser. No. 62/098,819 filed Dec. 31, 2014,U.S. Provisional Application Ser. No. 62/028,014 filed Jul. 23, 2014,U.S. Provisional Application Ser. No. 62/010,092 filed Jun. 10, 2014,and U.S. Provisional Application Ser. No. 61/991,656 filed May 12, 2014,the contents of which are s relied upon and incorporated herein byreference in their entirety.

BACKGROUND

The disclosure relates to durable anti-reflective articles and methodsfor making the same, and more particularly to articles with multi-layeranti-reflective coatings exhibiting abrasion resistance, lowreflectivity, and colorless transmittance and/or reflectance.

Cover articles are often used to protect critical devices withinelectronic products, to provide a user interface for input and/ordisplay, and/or many other functions. Such products include mobiledevices, such as smart phones, mp3 players and computer tablets. Coverarticles also include architectural articles, transportation articles(e.g., articles used in automotive applications, trains, aircraft, seacraft, etc.), appliance articles, or any article that requires sometransparency, scratch-resistance, abrasion resistance or a combinationthereof. These applications often demand scratch-resistance and strongoptical performance characteristics, in terms of maximum lighttransmittance and minimum reflectance. Furthermore, some coverapplications require that the color exhibited or perceived, inreflection and/or transmission, does not change appreciably as theviewing angle is changed. In display applications, this is because, ifthe color in reflection or transmission changes with viewing angle to anappreciable degree, the user of the product will perceive a change incolor or brightness of the display, which can diminish the perceivedquality of the display. In other applications, changes in color maynegatively impact the aesthetic requirements or other functionalrequirements.

The optical performance of cover articles can be improved by usingvarious anti-reflective coatings; however known anti-reflective coatingsare susceptible to wear or abrasion. Such abrasion can compromise anyoptical performance improvements achieved by the anti-reflectivecoating. For example, optical filters are often made from multilayercoatings having differing refractive indices and made from opticallytransparent dielectric material (e.g., oxides, nitrides, and fluorides).Most of the typical oxides used for such optical filters are wideband-gap materials, which do not have the requisite mechanicalproperties, such as hardness, for use in mobile devices, architecturalarticles, transportation articles or appliance articles. Nitrides anddiamond-like coatings may exhibit high hardness values but suchmaterials do not exhibit the transmittance needed for such applications.

Abrasion damage can include reciprocating sliding contact from counterface objects (e.g., fingers). In addition, abrasion damage can generateheat, which can degrade chemical bonds in the film materials and causeflaking and other types of damage to the cover glass. Since abrasiondamage is often experienced over a longer term than the single eventsthat cause scratches, the coating materials disposed experiencingabrasion damage can also oxidize, which further degrades the durabilityof the coating.

Accordingly, there is a need for new cover articles, and methods fortheir manufacture, which are abrasion resistant and have improvedoptical performance.

SUMMARY

Embodiments of durable, anti-reflective articles are described. In oneor more embodiments, the article includes a substrate and ananti-reflective coating having a thickness of about 1 μm or less (e.g.,about 800 nm or less) disposed on the major surface forming ananti-reflective surface. The article exhibits an abrasion resistance asmeasured on the anti-reflective surface after a 500-cycle abrasion usinga Taber Test, as described herein. In one or more embodiments, thearticle exhibits an abrasion resistance (as measured on theanti-reflective surface) comprising about 1% haze or less, as measuredusing a hazemeter having an aperture, wherein the aperture has adiameter of about 8 mm. In one or more embodiments, the article exhibitsan abrasion resistance (as measured on the anti-reflective surface)comprising an average roughness Ra, as measured by atomic forcemicroscopy, of about 12 nm or less. In one or more embodiments, thearticle exhibits an abrasion resistance (as measured on theanti-reflective surface) comprising a scattered light intensity of about0.05 (in units of 1/steradian) or less, at a polar scattering angle ofabout 40 degrees or less, as measured at normal incidence intransmission using an imaging sphere for scatter measurements, with a 2mm aperture at 600 nm wavelength. In some instances, the articleexhibits an abrasion resistance (as measured on the anti-reflectivesurface) comprising a scattered light intensity of about 0.1 (in unitsof 1/steradian) or less, at a polar scattering angle of about 20 degreesor less, as measured at normal incidence in transmission using animaging sphere for scatter measurements, with a 2 mm aperture at 600 nmwavelength.

The article of one or more embodiments exhibits superior opticalperformance in terms of light transmittance and/or light reflectance. Inone or more embodiments, the article exhibits an average lighttransmittance (measured on the anti-reflective surface) of about 94% orgreater (e.g., about 98% or greater) over an optical wavelength regime(e.g., in the range from about 400 nm to about 800 nm or from about 450nm to about 650 nm). In some embodiments, the article exhibits anaverage light reflectance (measured at the anti-reflective surface) ofabout 2% or less (e.g., about 1% or less) over the optical wavelengthregime. The article may exhibits an average light transmittance oraverage light reflectance having an average oscillation amplitude ofabout 1 percentage points or less over the optical wavelength regime. Insome instances, the article exhibits an angular color shift of less thanabout less than about 10 (e.g., 5 or less, 4 or less, 3 or less, 2 orless or about 1 or less) from a reference illumination angle to anincident illumination angle in the range from about 2 degrees to about60 degrees, when viewed at the anti-reflective surface using anilluminant. Exemplary illuminants include any one of CIE F2, CIE F10,CIE F11, CIE F12 and CIE D65. In one or more embodiment, the article mayexhibit a b* value of in the range from about −5 to about 1, from about−5 to about 0 or from about −4 to about 0, in the CIE L*, a*, b*colorimetry system at all incidence illumination angles in the rangefrom about 0 to about 60 degrees. Alternatively or additionally, thearticle of some embodiments exhibits a transmittance color (ortransmittance color coordinates) and/or a reflectance color (orreflectance color coordinates) measured at the anti-reflective surfacehaving a reference point color shift of less than about 2 from areference point, as defined herein. In one or more embodiments, thereference point may be the origin (0, 0) in the L*a*b* color space (orthe color coordinates a*=0, b*=0), the coordinates (a*=−2,b*=−2) or thetransmittance or reflectance color coordinates of the substrate. Theangular color shift, reference color shift and color coordinates (a*and/or b*) described herein are observed under a D65 and/or F2illuminant.

In one or more embodiments, the anti-reflective coating may include aplurality of layers. For example, in some embodiments, theanti-reflective coating includes a period comprising a first low RIlayer and a second high RI layer. The period may include a first low RIlayer and a second high RI disposed on the first low RI layer or viceversa. In some embodiments, the period may include a third layer. Theanti-reflective coating may include a plurality of periods such that thefirst low RI layer and the second high RI layer alternate. Theanti-reflective coating can include up to about 10 periods.

In one or more embodiments, at least one of the first low RI layer andthe second high RI layer includes an optical thickness (n*d) in therange from about 2 nm to about 200 nm. In some embodiments, theanti-reflective coating includes a plurality of layers with one or moresecond high RI layer(s) such that the combined thickness of the secondhigh RI layer(s) is less than about 500 nm or less.

In some embodiments, the article may include a layer having a refractiveindex greater than about 1.9. Materials that may be utilized in thatlayer include SiN_(x), SiO_(x)N_(y), Si_(n)Al_(v)O_(x)N_(y), AlN_(x),AlO_(x)N_(y) or a combination thereof.

In some instances, the article may include an additional layer, such asan easy-to-clean coating, a diamond-like carbon (“DLC”) coating, ascratch-resistant coating or a combination thereof. Such coatings may bedisposed on the anti-reflective coating or between layers of theanti-reflective coating. Where scratch resistant coatings are included,such coatings may be disposed on the anti-reflective coating and mayform a scratch resistant surface. Exemplary scratch resistant coatingsmay exhibit a hardness in the range from about 8 GPa to about 50 GPa asmeasured by a Berkovitch Indenter Hardness Test, as defined herein.

In some embodiments, the article may include a layer having a refractiveindex greater than about 1.9. Materials that may be utilized in thatlayer include SiN_(x), SiO_(x)N_(y), Si_(n)Al_(v)O_(x)N_(y), AlN_(x),AlO_(x)N_(y) or a combination thereof.

The substrate utilized in one or more embodiments of the article caninclude an amorphous substrate or a crystalline substrate. An of anamorphous substrate includes glass that may be selected from the groupconsisting of soda lime glass, alkali aluminosilicate glass, alkalicontaining borosilicate glass and alkali aluminoborosilicate glass. Insome embodiments, the glass may be strengthened and may include acompressive stress (CS) layer with a surface CS of at least 250 MPaextending within the strengthened glass from a surface of the chemicallystrengthened glass to a depth of layer (DOL) of at least about 10 μm.

Additional features and advantages will be set forth in the detaileddescription which follows, and in part will be readily apparent to thoseskilled in the art from that description or recognized by practicing theembodiments as described herein, including the detailed descriptionwhich follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description are merely exemplary, and areintended to provide an overview or framework to understanding the natureand character of the claims. The accompanying drawings are included toprovide a further understanding, and are incorporated in and constitutea part of this specification. The drawings illustrate one or moreembodiment(s), and together with the description serve to explainprinciples and operation of the various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an article, according to one or moreembodiments;

FIG. 2 is a side view of an article, according to one or more specificembodiments;

FIG. 3 is a side view of an article, according to one or moreembodiments;

FIG. 4 is a side view of an article, according to one or moreembodiments;

FIG. 5 is a side view of an article, according to one or moreembodiments;

FIG. 6 is a side view of an article, according to one or moreembodiments;

FIG. 7 is a side view of an article according Example 1;

FIG. 8 is a graph showing the reflectance of the article according toExample 1;

FIG. 9 is graph showing the modeled reflectance of the article accordingto Example 2;

FIG. 10 is graph showing the modeled reflectance of the articleaccording to Example 3;

FIG. 11 is a graph showing the modeled reflectance of the articleaccording to Example 3, with an additional DLC coating;

FIG. 12 is an illustration of an article according to Example 4;

FIG. 13 is a single-sided reflectance spectra of the article of Example4, showing the reflectance as the incident illumination angle changesfrom 0° to about 60°;

FIG. 14 is a reflected color spectra of the article of Example 4 showingthe reflected color under different illuminants at different viewingangles, using a 10° observer;

FIG. 15 is an illustration of an article according to Example 5;

FIG. 16 is a single-sided reflectance spectra of the article of Example5, showing the reflectance as the incident illumination angle changesfrom 0° to about 45°;

FIG. 17 is a reflected color spectra of the article of Example 5 showingthe reflected color under a D65 illuminant at different viewing angles,using a 10° observer;

FIG. 18 is an illustration of an article according to Example 6;

FIG. 19 is a single-sided reflectance spectra of the article of Example6, showing the reflectance as the incident illumination angle changesfrom 0° to about 60°;

FIG. 20 is a reflected color spectra of the article of Example 6 showingthe reflected color under different illuminants at different viewingangle, using a 10° observer;

FIG. 21 is an illustration of an article according to Example 7;

FIG. 22 is a single-sided reflectance spectra of the article of Example7, showing the reflectance as the incident illumination angle changesfrom 0° to about 60°;

FIG. 23 is a reflected color spectra of the article of Example 7 showingthe reflected color under different illuminants at different viewingangle, using a 10° observer;

FIG. 24 is an illustration of an article according to Example 8;

FIG. 25 is a single-sided reflectance spectra of the article of Example8, showing the reflectance as the incident illumination angle changesfrom 0° to about 60°;

FIG. 26 is a reflected color spectra of the article of Example 8 showingthe reflected color under different illuminants at different viewingangle, using a 10° observer;

FIG. 27 is a single-sided reflectance spectra of the article of modeledExample 9, showing the reflectance as the incident illumination anglechanges from 0° to about 60°;

FIG. 28 is a reflected color spectra of the article of Example 9 showingthe reflected color under different illuminants at different viewingangle, using a 10° observer;

FIG. 29 is a single-sided reflectance spectra of the article of modeledExample 10A, showing the reflectance as the incident illumination anglechanges from 0° to about 60°;

FIG. 30 is a single-sided reflectance spectra of the article of modeledExample 10B, showing the reflectance as the incident illumination anglechanges from 0° to about 60°;

FIG. 31 is a reflected color spectra of the article of Example 1 OAshowing the reflected color under different illuminants at differentviewing angle, using a 10° observer;

FIG. 32 is a reflected color spectra of the article of Example 10Bshowing the reflected color under different illuminants at differentviewing angle, using a 10° observer;

FIG. 33 is a graph showing scattered light intensity values measured forExamples 12 and 13 and Comparative Examples 15, 16, and 17 after andwithout being subjected to the Taber Test;

FIG. 34 is a graph showing the AFM roughness statistics measured forExamples 12 and 13 and Comparative Examples 14, 17 and 18 after beingsubjected to the Taber Test;

FIG. 35 is a single-sided reflectance spectra of the article of Example19, showing the reflectance as the incident illumination angle changesfrom 0° to about 60°;

FIG. 36 is a reflected and transmitted color spectra of the article ofExample 19 showing the reflected and transmitted color under differentilluminants at different viewing angle, using a 10° observer;

FIG. 37 is an graph showing the measured transmittance color coordinatesand reflectance color coordinates of Example 21;

FIG. 38 is the reflectance spectrum for Example 21 at differentillumination angles;

FIG. 39 is a graph showing the two surface transmittance and reflectancespectra for Example 21;

FIG. 40 is a graph illustrating the hardness measurements as a functionof indentation depth and coating thickness.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments, examples ofwhich are illustrated in the accompanying drawings.

Referring to FIG. 1, the article 100 according to one or moreembodiments may include a substrate 110, and an anti-reflective coating120 disposed on the substrate. The substrate 110 includes opposing majorsurfaces 112, 114 and opposing minor surfaces 116, 118. Theanti-reflective coating 120 is shown in FIG. 1 as being disposed on afirst opposing major surface 112; however, the anti-reflective coating120 may be disposed on the second opposing major surface 114 and/or oneor both of the opposing minor surfaces, in addition to or instead ofbeing disposed on the first opposing major surface 112. Theanti-reflective coating 120 forms an anti-reflective surface 122.

The anti-reflective coating 120 includes at least one layer of at leastone material. The term “layer” may include a single layer or may includeone or more sub-layers. Such sub-layers may be in direct contact withone another. The sub-layers may be formed from the same material or twoor more different materials. In one or more alternative embodiments,such sub-layers may have intervening layers of different materialsdisposed therebetween. In one or more embodiments a layer may includeone or more contiguous and uninterrupted layers and/or one or morediscontinuous and interrupted layers (i.e., a layer having differentmaterials formed adjacent to one another). A layer or sub-layers may beformed by any known method in the art, including discrete deposition orcontinuous deposition processes. In one or more embodiments, the layermay be formed using only continuous deposition processes, or,alternatively, only discrete deposition processes.

As used herein, the term “dispose” includes coating, depositing and/orforming a material onto a surface using any known method in the art. Thedisposed material may constitute a layer, as defined herein. The phrase“disposed on” includes the instance of forming a material onto a surfacesuch that the material is in direct contact with the surface and alsoincludes the instance where the material is formed on a surface, withone or more intervening material(s) is between the disposed material andthe surface. The intervening material(s) may constitute a layer, asdefined herein.

The anti-reflective coating 120 of one or more embodiments may bedescribed as abrasion resistant as measured by various methods, afterbeing abraded according to a Taber Test after at least about 500 cycles.Various forms of abrasion test are known in the art, such as the testmethod specified in ASTM D1044-99, using abrasive media supplied byTaber Industries. Modified abrasion methods related to ASTM D1044-99 canbe created using different types of abrading media, abradant geometryand motion, pressure, etc. in order to provide repeatable and measurableabrasion or wear tracks to meaningfully differentiate the abrasionresistance of different samples. For example, different test conditionswill usually be appropriate for soft plastics vs. hard inorganic testsamples. The embodiments described herein were subjected to a TaberTest, as defined herein, which is a specific modified version of ASTMD1044-99 that gives clear and repeatable differentiation of durabilitybetween different samples which comprise primarily hard inorganicmaterials, such as oxide glasses and oxide or nitride coatings. As usedherein, the phrase “Taber Test” refers to a test method using a TaberLinear Abraser 5750 (TLA 5750) and accessories supplied by TaberIndustries, in an environment including a temperature of about 22° C.±3°C. and Relative Humidity of up to about 70%. The TLA 5750 includes aCS-17 abraser material having a 6.7 mm diameter abraser head. Eachsample was abraded according to the Taber Test and the abrasive damagewas evaluated using both Haze and Bidirectional TransmittanceDistribution Function (CCBTDF) measurements, among other methods. In theTaber Test, the procedure for abrading each sample includes placing theTLA 5750 and a flat sample support on a rigid, flat surface and securingthe TLA 5750 and the sample support to the surface. Before each sampleis abraded under the Taber Test, the abraser is refaced using a new S-14refacing strip adhered to glass. The abraser is subjected to 10 refacingcycles using a cycle speed of 25 cycles/minute and stroke length of 1inch, with no additional weight added (i.e., a total weight of about 350g is used during refacing, which is the combined weight of the spindleand collet holding the abraser). The procedure then includes operatingthe TLA 5750 to abrade the sample, where the sample is placed in thesample support in contact with the abraser head and supporting theweight applied to the abraser head, using a cycle speed of 25cycles/minute, and a stroke length of 1 inch, and a weight such that thetotal weight applied to the sample is 850 g (i.e., a 500 g auxiliaryweight is applied in addition to the 350 g combined weight of thespindle and collet). The procedure includes forming two wear tracks oneach sample for repeatability, and abrading each sample for 500 cyclecounts in each of the two wear tracks on each sample.

In one or more embodiments, the anti-reflective coating 120 of thearticle 100 is abraded according to the above Taber Test and the articleexhibits a haze of about 10% of less, as measured on the abraded sideusing a hazemeter supplied by BYK Gardner under the trademark Haze-GardPlus®, using an aperture over the source port, the aperture having adiameter of 8 mm.

The article 100 of one or more embodiments exhibits such abrasionresistance with and without any additional coatings (including theadditional coating 140, which will be described herein). In someembodiments, the haze may be about 9% or less, about 8% or less, about7% or less, about 6% or less, about 5% or less, about 4% or less, about3% or less, about 2% or less, about 1% or less, about 0.5% or less orabout 0.3% or less. In some specific embodiments, the article 100exhibits a haze in the range from about 0.1% to about 10%, from about0.1% to about 9%, from about 0.1% to about 8%, from about 0.1% to about7%, from about 0.1% to about 6%, from about 0.1% to about 5%, from about0.1% to about 4%, from about 0.1% to about 3%, from about 0.1% to about2%, from about 0.1% to about 1%, 0.3% to about 10%, from about 0.5% toabout 10%, from about 1% to about 10%, from about 2% to about 10%, fromabout 3% to about 10%, from about 4% to about 10%, from about 5% toabout 10%, from about 6% to about 10%, from about 7% to about 10%, fromabout 1% to about 8%, from about 2% to about 6%, from about 3% to about5%, and all ranges and sub-ranges therebetween.

Alternate methods for quantifying the abrasion resistance are alsocontemplated here. In one or more embodiments, article 100 abraded bythe Taber Test on the anti-reflective coating 120 may exhibit anabrasion resistance as measured by atomic force microscopy (AFM) surfaceprofiling, which may be carried out for example over an 80×80 micronarea, or multiple 80×80 micron areas (to sample a larger portion of theabraded area) of the anti-reflective coating 120. From these AFM surfacescans, surface roughness statistics such as RMS roughness, Ra roughness,and peak-to-valley surface height may be evaluated. In one or moreembodiments, the article 100 (or specifically, the anti-reflectivecoating 120) may exhibit average surface roughness (Ra) values of about50 nm or less, about 25 nm or less, about 12 nm or less, about 10 nm orless, or about 5 nm or less, after being abraded under the Taber Testdescribed above.

In one or more embodiments, the article 100 may exhibit an abrasionresistance, after being abraded by the Taber Test as measured by a lightscattering measurement. In one or more embodiments, the light scatteringmeasurement includes a bi-directional reflectance distribution function(BRDF) or bi-directional transmittance distribution function (BTDF)measurement carried out using a Radiant Zemax IS-SA™ instrument. Thisinstrument has the flexibility to measure light scattering using anyinput angle from normal to about 85 degrees incidence in reflection, andfrom normal to about 85 degrees incidence in transmission, while alsocapturing all scattered light output in either reflection ortransmission into 2*Pi steradians (a full hemisphere in reflection ortransmission). In one embodiment, the article 100 exhibits an abrasionresistance, as measured using BTDF at normal incidence and analyzing thetransmitted scattered light at a selected angular range, for examplefrom about 10° to about 80° degrees in polar angles and any angularrange therein. The full azimuthal range of angles can be analyzed andintegrated, or particular azimuthal angular slices can be selected, forexample from about 0° and 90° azimuthally. In the case of linearabrasion, it may be desired to choose an azimuthal direction that issubstantially orthogonal to the abrasion direction so as to increasesignal-to-noise of the optical scattering measurement. In one or moreembodiments, the article 100 may exhibit a scattered light intensity asmeasured at the anti-reflective coating 120, of about less than about0.1, about 0.05 or less, about 0.03 or less, about 0.02 or less, about0.01 or less, about 0.005 or less, or about 0.003 or less (in units of1/steradian), when using the Radiant Zemax IS-SA tool in CCBTDF mode atnormal incidence in transmission, with a 2 mm aperture and amonochrometer set to 600 nm wavelength, and when evaluated at polarscattering angles in the range from about 15° to about 60° (e.g.specifically, about 20° or about 40°). Normal incidence in transmissionmay be otherwise known as zero degrees in transmission, which may bedenoted as 180° incidence by the instrument software. In one or moreembodiments, the scattered light intensity may be measured along anazimuthal direction substantially orthogonal to the abraded direction ofa sample abraded by the Taber Test. In one example, the Taber Test mayuse from about 10 cycles to about 1000 cycles, and all values inbetween. These optical intensity values may also correspond to less thanabout 1%, less than about 0.5%, less than about 0.2%, or less than about0.1% of the input light intensity that is scattered into polarscattering angles greater than about 5 degrees, greater than about 10degrees, greater than about 30 degrees, or greater than about 45degrees.

Generally speaking, BTDF testing at normal incidence, as describedherein, is closely related to the transmission haze measurement, in thatboth are measuring the amount of light that is scattered in transmissionthrough a sample (or, in this case the article 100, after abrading theanti-reflective coating 120). BTDF measurements provide more sensitivityas well as more detailed angular information, compared to hazemeasurements. BTDF allows measurement of scattering into different polarand azimuthal angles, for example allowing us to selectively evaluatethe scattering into azimuthal angles that are substantially orthogonalto the abrasion direction in the linear Taber test (these are the angleswhere light scattering from linear abrasion is the highest).Transmission haze is essentially the integration of all scattered lightmeasured by normal incidence BTDF into the entire hemisphere of polarangles greater than about +/−2.5 degrees.

The anti-reflective coating 120 and the article 100 may be described interms of a hardness measured by a Berkovich Indenter Hardness Test. Asused herein, the “Berkovich Indenter Hardness Test” includes measuringthe hardness of a material on a surface thereof by indenting the surfacewith a diamond Berkovich indenter. The Berkovich Indenter Hardness Testincludes indenting the anti-reflective surface 122 of the article or thesurface of the anti-reflective coating 120 (or the surface of any one ormore of the layers in the anti-reflective coating) with the diamondBerkovich indenter to form an indent to an indentation depth in therange from about 50 nm to about 1000 nm (or the entire thickness of theanti-reflective coating or layer, whichever is less) and measuring themaximum hardness from this indentation along the entire indentationdepth range or a segment of this indentation depth (e.g., in the rangefrom about 100 nm to about 600 nm), generally using the methods setforth in Oliver, W. C.; Pharr, G. M. An improved technique fordetermining hardness and elastic modulus using load and displacementsensing indentation experiments. J. Mater. Res., Vol. 7, No. 6, 1992,1564-1583; and Oliver, W. C.; Pharr, G. M. Measurement of Hardness andElastic Modulus by Instrument Indentation: Advances in Understanding andRefinements to Methodology. J. Mater. Res., Vol. 19, No. 1, 2004, 3-20.As used herein, hardness refers to a maximum hardness, and not anaverage hardness.

Typically, in nanoindentation measurement methods (such as by using aBerkovich indenter) of a coating that is harder than the underlyingsubstrate, the measured hardness may appear to increase initially due todevelopment of the plastic zone at shallow indentation depths and thenincreases and reaches a maximum value or plateau at deeper indentationdepths. Thereafter, hardness begins to decrease at even deeperindentation depths due to the effect of the underlying substrate. Wherea substrate having an increased hardness compared to the coating isutilized, the same effect can be seen; however, the hardness increasesat deeper indentation depths due to the effect of the underlyingsubstrate.

The indentation depth range and the hardness values at certainindentation depth range(s) can be selected to identify a particularhardness response of the optical film structures and layers thereof,described herein, without the effect of the underlying substrate. Whenmeasuring hardness of the optical film structure (when disposed on asubstrate) with a Berkovich indenter, the region of permanentdeformation (plastic zone) of a material is associated with the hardnessof the material. During indentation, an elastic stress field extendswell beyond this region of permanent deformation. As indentation depthincreases, the apparent hardness and modulus are influenced by stressfield interactions with the underlying substrate. The substrateinfluence on hardness occurs at deeper indentation depths (i.e.,typically at depths greater than about 10% of the optical film structureor layer thickness). Moreover, a further complication is that thehardness response requires a certain minimum load to develop fullplasticity during the indentation process. Prior to that certain minimumload, the hardness shows a generally increasing trend.

At small indentation depths (which also may be characterized as smallloads) (e.g., up to about 50 nm), the apparent hardness of a materialappears to increase dramatically versus indentation depth. This smallindentation depth regime does not represent a true metric of hardnessbut instead, reflects the development of the aforementioned plasticzone, which is related to the finite radius of curvature of theindenter. At intermediate indentation depths, the apparent hardnessapproaches maximum levels. At deeper indentation depths, the influenceof the substrate becomes more pronounced as the indentation depthsincrease. Hardness may begin to drop dramatically once the indentationdepth exceeds about 30% of the optical film structure thickness or thelayer thickness.

FIG. 40 illustrates the changes in measured hardness value as a functionof indentation depth and thickness of a coating. As shown in FIG. 40,the hardness measured at intermediate indentation depths (at whichhardness approaches and is maintained at maximum levels) and at deeperindentation depths depends on the thickness of a material or layer. FIG.40 illustrates the hardness response of four different layers ofAlO_(x)N_(y) having different thicknesses. The hardness of each layerwas measured using the Berkovich Indenter Hardness Test. The 500nm-thick layer exhibited its maximum hardness at indentation depths fromabout 100 nm to 180 nm, followed by a dramatic decrease in hardness atindentation depths from about 180 nm to about 200 nm, indicating thehardness of the substrate influencing the hardness measurement. The 1000nm-thick layer exhibited a maximum hardness at indentation depths fromabout 100 nm to about 300 nm, followed by a dramatic decrease inhardness at indentation depths greater than about 300 nm. The 1500nm-thick layer exhibited a maximum hardness at indentation depths fromabout 100 nm to about 550 nm and the 2000-nm thick layer exhibited amaximum hardness at indentation depths from about 100 nm to about 600nm. Although FIG. 40 illustrates a thick single layer, the same behavioris observed in thinner coatings and those including multiple layers suchas the anti-reflective coating 120 of the embodiments described herein.

In some embodiments, the anti-reflective coating 120 may exhibit ahardness of greater than about 5 GPa, as measured on the anti-reflectivesurface 122, by a Berkovitch Indenter Hardness Test. The antireflectivecoating 120 may exhibit a hardness of about 8 GPa or greater, about 10GPa or greater or about 12 GPa or greater. The article 100, includingthe anti-reflective coating 120 and any additional coatings, asdescribed herein, may exhibit a hardness of about 5 GPa or greater,about 8 GPa or greater, about 10 GPa or greater or about 12 GPa orgreater, as measured on the anti-reflective surface 122, by a BerkovitchIndenter Hardness Test. Such measured hardness values may be exhibitedby the anti-reflective coating 120 and/or the article 100 along anindentation depth of about 50 nm or greater or about 100 nm or greater(e.g., from about 100 nm to about 300 nm, from about 100 nm to about 400nm, from about 100 nm to about 500 nm, from about 100 nm to about 600nm, from about 200 nm to about 300 nm, from about 200 nm to about 400nm, from about 200 nm to about 500 nm, or from about 200 nm to about 600nm).

The anti-reflective coating 120 may have at least one layer having ahardness (as measured on the surface of such layer, e.g., surface of thesecond high RI layer 130B of FIG. 2) of about 12 GPa or greater, about13 GPa or greater, about 14 GPa or greater, about 15 GPa or greater,about 16 GPa or greater, about 17 GPa or greater, about 18 GPa orgreater, about 19 GPa or greater, about 20 GPa or greater, about 22 GPaor greater, about 23 GPa or greater, about 24 GPa or greater, about 25GPa or greater, about 26 GPa or greater, or about 27 GPa or greater (upto about 50 GPa), as measured by the Berkovich Indenter Hardness Test.The hardness of such layer may be in the range from about 18 GPa toabout 21 GPa, as measured by the Berkovich Indenter Hardness Test. Suchmeasured hardness values may be exhibited by the at least one layeralong an indentation depth of about 50 nm or greater or 100 nm orgreater (e.g., from about 100 nm to about 300 nm, from about 100 nm toabout 400 nm, from about 100 nm to about 500 nm, from about 100 nm toabout 600 nm, from about 200 nm to about 300 nm, from about 200 nm toabout 400 nm, from about 200 nm to about 500 nm, or from about 200 nm toabout 600 nm). In one or more embodiments, the article exhibits ahardness that is greater than the hardness of the substrate (which canbe measured on the opposite surface from the anti-reflective surface).

In one or more embodiments, the anti-reflective coating 120 orindividual layers within the anti-reflective coating may exhibit anelastic modulus of about 75 GPa or greater, about 80 GPa or greater orabout 85 GPa or greater, as measured on the anti-reflective surface 122,by indenting that surface with a Berkovitch indenter. These modulusvalues may represent a modulus measured very close to theanti-reflective surface 122, e.g. at indentation depths of 0-50 nm, orit may represent a modulus measured at deeper indentation depths, e.g.from about 50-1000 nm.

Optical interference between reflected waves from the anti-reflectivecoating 120/air interface and the anti-reflective coating 120/substrate110 interface can lead to spectral reflectance and/or transmittanceoscillations that create apparent color in the article 100. As usedherein, the term “transmittance” is defined as the percentage ofincident optical power within a given wavelength range transmittedthrough a material (e.g., the article, the substrate or the optical filmor portions thereof). The term “reflectance” is similarly defined as thepercentage of incident optical power within a given wavelength rangethat is reflected from a material (e.g., the article, the substrate, orthe optical film or portions thereof). Transmittance and reflectance aremeasured using a specific linewidth. In one or more embodiments, thespectral resolution of the characterization of the transmittance andreflectance is less than 5 nm or 0.02 eV. The color may be morepronounced in reflection. The angular color shifts in reflection withviewing angle due to a shift in the spectral reflectance oscillationswith incident illumination angle. Angular color shifts in transmittancewith viewing angle are also due to the same shift in the spectraltransmittance oscillation with incident illumination angle. The observedcolor and angular color shifts with incident illumination angle areoften distracting or objectionable to device users, particularly underillumination with sharp spectral features such as fluorescent lightingand some LED lighting. Angular color shifts in transmission may alsoplay a factor in angular color shift in reflection and vice versa.Factors in angular color shifts in transmission and/or reflection mayalso include angular color shifts due to viewing angle or color shiftsaway from a certain white point that may be caused by materialabsorption (somewhat independent of angle) defined by a particularilluminant or test system.

The oscillations may be described in terms of amplitude. As used herein,the term “amplitude” includes the peak-to-valley change in reflectanceor transmittance. The phrase “average amplitude” includes thepeak-to-valley change in reflectance or transmittance averaged withinthe optical wavelength regime. As used herein, the “optical wavelengthregime” includes the wavelength range from about 400 nm to about 800 nm(and more specifically from about 450 nm to about 650 nm).

The embodiments of this disclosure include an anti-reflective coating toprovide improved optical performance, in terms of colorlessness and/orsmaller angular color shifts with viewed at varying incidentillumination angles from normal incidence under different illuminants.

One aspect of this disclosure pertains to an article that exhibitscolorlessness in reflectance and/or transmittance even when viewed atdifferent incident illumination angles under an illuminant. In one ormore embodiments, the article exhibits an angular color shift inreflectance and/or transmittance of about 5 or less or about 2 or lessbetween a reference illumination angle and any incidental illuminationangles, in the ranges provided herein. As used herein, the phrase “colorshift” (angular or reference point) refers to the change in both a* andb*, under the CIE L*, a*, b* colorimetry system in reflectance and/ortransmittance. It should be understood that unless otherwise noted, theL* coordinate of the articles described herein are the same at any angleor reference point and do not influence color shift. For example,angular color shift may be determined using the following Equation (1):

√((a* ₂ −a* ₁)²+(b* ₂ −b* ₁)²)  (1)

with a*₁, and b*₁ representing the a* and b* coordinates of the articlewhen viewed at a reference illumination angle (which may include normalincidence) and a*₂, and b*₂ representing the a* and b* coordinates ofthe article when viewed at an incident illumination angle, provided thatthe incident illumination angle is different from reference illuminationangle and in some cases differs from the reference illumination angle byat least about 1 degree, 2 degrees or about 5 degrees. In someinstances, an angular color shift in reflectance and/or transmittance ofabout 10 or less (e.g., 5 or less, 4 or less, 3 or less, or 2 or less)is exhibited by the article when viewed at various incident illuminationangles from a reference illumination angle, under an illuminant. In someinstances the angular color shift in reflectance and/or transmittance isabout 1.9 or less, 1.8 or less, 1.7 or less, 1.6 or less, 1.5 or less,1.4 or less, 1.3 or less, 1.2 or less, 1.1 or less, 1 or less, 0.9 orless, 0.8 or less, 0.7 or less, 0.6 or less, 0.5 or less, 0.4 or less,0.3 or less, 0.2 or less, or 0.1 or less. In some embodiments, theangular color shift may be about 0. The illuminant can include standardilluminants as determined by the CIE, including A illuminants(representing tungsten-filament lighting), B illuminants (daylightsimulating illuminants), C illuminants (daylight simulatingilluminants), D series illuminants (representing natural daylight), andF series illuminants (representing various types of fluorescentlighting). In specific examples, the articles exhibit an angular colorshift in reflectance and/or transmittance of about 2 or less when viewedat incident illumination angle from the reference illumination angleunder a CIE F2, F10, F11, F12 or D65 illuminant or more specificallyunder a CIE F2 illuminan.

The reference illumination angle may include normal incidence (i.e., 0degrees), or 5 degrees from normal incidence, 10 degrees from normalincidence, 15 degrees from normal incidence, 20 degrees from normalincidence, 25 degrees from normal incidence, 30 degrees from normalincidence, 35 degrees from normal incidence, 40 degrees from normalincidence, 50 degrees from normal incidence, 55 degrees from normalincidence, or 60 degrees from normal incidence, provided the differencebetween the reference illumination angle and the difference between theincident illumination angle and the reference illumination angle is atleast about 1 degree, 2 degrees or about 5 degrees. The incidentillumination angle may be, with respect to the reference illuminationangle, in the range from about 5 degrees to about 80 degrees, from about5 degrees to about 80 degrees, from about 5 degrees to about 70 degrees,from about 5 degrees to about 65 degrees, from about 5 degrees to about60 degrees, from about 5 degrees to about 55 degrees, from about 5degrees to about 50 degrees, from about 5 degrees to about 45 degrees,from about 5 degrees to about 40 degrees, from about 5 degrees to about35 degrees, from about 5 degrees to about 30 degrees, from about 5degrees to about 25 degrees, from about 5 degrees to about 20 degrees,from about 5 degrees to about 15 degrees, and all ranges and sub-rangestherebetween, away from normal incidence. The article may exhibit theangular color shifts in reflectance and/or transmittance describedherein at and along all the incident illumination angles in the rangefrom about 2 degrees to about 80 degrees, when the referenceillumination angle is normal incidence. In some embodiments, the articlemay exhibit the angular color shifts in reflectance and/or transmittancedescribed herein at and along all the incident illumination angles inthe range from about 2 degrees to about 80 degrees, when the differencebetween the incident illumination angle and the reference illuminationangle is at least about 1 degree, 2 degrees or about 5 degrees. In oneexample, the article may exhibit an angular color shift in reflectanceand/or transmittance of 2 or less at any incident illumination angle inthe range from about 2 degrees to about 60 degrees, from about 5 degreesto about 60 degrees, or from about 10 degrees to about 60 degrees awayfrom a reference illumination angle equal to normal incidence. In otherexamples, the article may exhibit an angular color shift in reflectanceand/or transmittance of 2 or less when the reference illumination angleis 10 degrees and the incident illumination angle is any angle in therange from about 12 degrees to about 60 degrees, from about 15 degreesto about 60 degrees, or from about 20 degrees to about 60 degrees awayfrom the reference illumination angle.

In some embodiments, the angular color shift may be measured at allangles between a reference illumination angle (e.g., normal incidence)and an incident illumination angle in the range from about 20 degrees toabout 80 degrees. In other words, the angular color shift may bemeasured and may be less than about 5 or less than about 2, at allangles in the range from about 0 degrees and 20 degrees, from about 0degrees to about 30 degrees, from about 0 degrees to about 40 degrees,from about 0 degrees to about 50 degrees, from about 0 degrees to about60 degrees or from about 0 degrees to about 80 degrees.

In one or more embodiments, the article exhibits a color in the CIE L*,a*, b* colorimetry system in reflectance and/or transmittance such thatthe distance or reference point color shift between the transmittancecolor or reflectance coordinates from a reference point is less thanabout 5 or less than about 2 under an illumaint (which can includestandard illuminants as determined by the CIE, including A illuminants(representing tungsten-filament lighting), B illuminants (daylightsimulating illuminants), C illuminants (daylight simulatingilluminants), D series illuminants (representing natural daylight), andF series illuminants (representing various types of fluorescentlighting)). In specific examples, the articles exhibit a color shift inreflectance and/or transmittance of about 2 or less when viewed atincident illumination angle from the reference illumination angle undera CIE F2, F10, F11, F12 or D65 illuminant or more specifically under aCIE F2 illuminant. Stated another way, the article may exhibit atransmittance color (or transmittance color coordinates) and/or areflectance color (or reflectance color coordinates) measured at theanti-reflective surface 122 having a reference point color shift of lessthan about 2 from a reference point, as defined herein. Unless otherwisenoted, the transmittance color or transmittance color coordinates aremeasured on two surfaces of the article including at the anti-reflectivesurface 122 and the opposite bare surface of the article (i.e., 114).Unless otherwise noted, the reflectance color or reflectance colorcoordinates are measured on only the anti-reflective surface 122 of thearticle.

In one or more embodiments, the reference point may be the origin (0, 0)in the CIE L*, a*, b* colorimetry system (or the color coordinates a*=0,b*=0), color coordinates (−2, −2) or the transmittance or reflectancecolor coordinates of the substrate. It should be understood that unlessotherwise noted, the L* coordinate of the articles described herein arethe same as the reference point and do not influence color shift. Wherethe reference point color shift of the article is defined with respectto the substrate, the transmittance color coordinates of the article arecompared to the transmittance color coordinates of the substrate and thereflectance color coordinates of the article are compared to thereflectance color coordinates of the substrate.

In one or more specific embodiments, the reference point color shift ofthe transmittance color and/or the reflectance color may be less than 1or even less than 0.5. In one or more specific embodiments, thereference point color shift for the transmittance color and/or thereflectance color may be 1.8, 1.6, 1.4, 1.2, 0.8, 0.6, 0.4, 0.2, 0 andall ranges and sub-ranges therebetween. Where the reference point is thecolor coordinates a*=0, b*=0, the reference point color shift iscalculated by Equation (2).

reference point color shift=√((a* _(article))²+(b* _(article))²)  (2)

Where the reference point is the color coordinates a*=−2, b*=−2, thereference point color shift is calculated by Equation (3).

reference point color shift=√(a* _(article)+2)²+(b* _(article)+2)²)  (3)

Where the reference point is the color coordinates of the substrate, thereference point color shift is calculated by Equation (4).

reference point color shift=√((a* _(article) −a* _(substrate))²+(b*_(article) −b* _(substrate))²)  (4)

In some embodiments, the article may exhibit a transmittance color (ortransmittance color coordinates) and a reflectance color (or reflectancecolor coordinates) such that the reference point color shift is lessthan 2 when the reference point is any one of the color coordinates ofthe substrate, the color coordinates a*=0, b*=0 and the coordinatesa*=−2, b*=−2.

In one or more embodiment, the article may exhibit a b* value inreflectance (as measured at the anti-reflective surface only) in therange from about −5 to about 1, from about −5 to about 0, from about −4to about 1, or from about −4 to about 0, in the CIE L*, a*, b*colorimetry system at all incidence illumination angles in the rangefrom about 0 to about 60 degrees (or from about 0 degrees to about 40degrees or from about 0 degrees to about 30 degrees).

In one or more embodiment, the article may exhibit a b* value intransmittance (as measured at the anti-reflective surface and theopposite bare surface of the article) in the range from about −2 toabout 2, from about −1 to about 2, from about −0.5 to about 2, fromabout 0 to about 2, from about 0 to about 1, from about −2 to about 0.5,from about −2 to about 1, from about −1 to about 1, or from about 0 toabout 0.5, in the CIE L*, a*, b* colorimetry system at all incidenceillumination angles in the range from about 0 to about 60 degrees (orfrom about 0 degrees to about 40 degrees or from about 0 degrees toabout 30 degrees).

In some embodiments, the article exhibits an a* value in transmittance(at the anti-reflective surface and the opposite bare surface) in therange from about −1.5 to about 1.5 (e.g., −1.5 to −1.2, −1.5 to −1, −1.2to 1.2, −1 to 1, −1 to 0.5, or −1 to 0) at incident illumination anglesin the range from about 0 degrees to about 60 degrees under illuminantsD65, A, and F2. In some embodiments, the article exhibits a b* value intransmittance (at the anti-reflective surface and the opposite baresurface) in the range from about −1.5 to about 1.5 (e.g., −1.5 to −1.2,−1.5 to −1, −1.2 to 1.2, −1 to 1, −1 to 0.5, or −1 to 0) at incidentillumination angles in the range from about 0 degrees to about 60degrees under illuminants D65, A, and F2.

In some embodiments, the article exhibits an a* value in reflectance (atonly the anti-reflective surface) in the range from about −5 to about 2(e.g., −4.5 to 1.5, −3 to 0, −2.5 to 0.25) at incident illuminationangles in the range from about 0 degrees to about 60 degrees underilluminants D65, A, and F2. In some embodiments, the article exhibits ab* value in reflectance (at only the anti-reflective surface) in therange from about −7 to about −1.5 at incident illumination angles in therange from about 0 degrees to about 60 degrees under illuminants D65, A,and F2.

The article of one or more embodiments, or the anti-reflective surface122 of one or more articles, may exhibit an average light transmittanceof about 95% or greater (e.g., about 9.5% or greater, about 96% orgreater, about 96.5% or greater, about 97% or greater, about 97.5% orgreater, about 98% or greater, about 98.5% or greater or about 99% orgreater) over the optical wavelength regime in the range from about 400nm to about 800 nm. In some embodiments, the article, or theanti-reflective surface 122 of one or more articles, may exhibit anaverage light reflectance of about 2% or less (e.g., about 1.5% or less,about 1% or less, about 0.75% or less, about 0.5% or less, or about0.25% or less) over the optical wavelength regime in the range fromabout 400 nm to about 800 nm. These light transmittance and lightreflectance values may be observed over the entire optical wavelengthregime or over selected ranges of the optical wavelength regime (e.g., a100 nm wavelength range, 150 nm wavelength range, a 200 nm wavelengthrange, a 250 nm wavelength range, a 280 nm wavelength range, or a 300 nmwavelength range, within the optical wavelength regime). In someembodiments, these light reflectance and transmittance values may be atotal reflectance or total transmittance (taking into accountreflectance or transmittance on both the anti-reflective surface 122 andthe opposite major surfaces, 114). Unless otherwise specified, theaverage reflectance or transmittance is measured at an incidentillumination angle of 0 degrees (however, such measurements may beprovided at incident illumination angles of 45 degrees or 60 degrees).

In some embodiments, the article of one or more embodiments, or theanti-reflective surface 122 of one or more articles, may exhibit anaverage visible photopic reflectance of about 1% or less, about 0.7% orless, about 0.5% or less, or about 0.45% or less over the opticalwavelength regime. These photopic reflectance values may be exhibited atincident illumination angles in the range from about 0° to about 20°,from about 0° to about 40° or from about 0° to about 60°. As usedherein, photopic reflectance mimics the response of the human eye byweighting the reflectance versus wavelength spectrum according to thehuman eye's sensitivity. Photopic reflectance may also be defined as theluminance, or tristimulus Y value of reflected light, according to knownconventions such as CIE color space conventions. The average photopicreflectance is defined in Equation (5) as the spectral reflectance, R(λ)multiplied by the illuminant spectrum, I(λ) and the CIE's color matchingfunction y(λ), related to the eye's spectral response:

$\begin{matrix}{{\langle R_{p}\rangle} = {\underset{380\mspace{14mu} {nm}}{\int\limits^{720\mspace{14mu} {nm}}}{{R(\lambda)} \times {I(\lambda)} \times {\overset{\_}{y}(\lambda)}{(\lambda)}}}} & (5)\end{matrix}$

In a specific embodiment, the anti-reflective surface 122 of one or morearticles (i.e. when measuring the anti-reflective surface 122 onlythrough a single-sided measurement), may exhibit an average visiblephotopic reflectance of about 2% or less, 1.8% or less, 1.5% or less,1.2% or less, 1% or less, 0.9% or less, 0.7% or less, about 0.5% orless, about 0.45% or less, about 0.4% or less, or about 0.35% or less.In some cases, the average visible photopic reflectance ranges areexhibited while simultaneously exhibiting a maximum reflectance colorshift, over the entire incident illumination angle range from about 5degrees to about 60 degrees (with the reference illumination angle beingnormal incidence) using D65 illumination, of less than about 5.0, lessthan about 4.0, less than about 3.0, less than about 2.0, less thanabout 1.5, or less than about 1.25. These maximum reflectance colorshift values represent the lowest color point value measured at anyangle from about 5 degrees to about 60 degrees from normal incidence,subtracted from the highest color point value measured at any angle inthe same range. The values may represent a maximum change in a* value(a*_(highest)−a*_(lowest)), a maximum change in b* value(b*_(highest)−b*_(lowest)), a maximum change in both a* and b* values,or a maximum change in the quantity√(a_(highest)−a_(lowest))²+(b*_(highest)−b*_(lowest))²).

In one or more embodiments, the article may exhibit a reflectancespectra, measured at the anti-reflective surface only, at or near normalincidence (e.g., from about 0 to about 10 degrees or from about 0degrees to about 6 degrees) that can be characterized in terms of thefollowing features: a maximum reflectance and a minimum reflectance overthe wavelength range from about 400 nm to about 480 nm (the maximumreflectance over this range is referred to as R400-max and the minimumreflectance over this range is referred to as R400-min), a maximumreflectance and a minimum reflectance over the wavelength range fromabout 500 nm to about 600 nm (the maximum reflectance over this range isreferred to as R500-max and the minimum reflectance over this range isreferred to as R500-min, respectively), and a maximum reflectance and aminimum reflectance in the wavelength range from about 640 nm to about710 nm (the maximum reflectance over the wavelength range from about 640nm to about 710 nm is referred to as R640-max the minimum reflectanceover the wavelength range from about 640 nm to about 710 nm is referredto as R640-min). In some embodiments, the reflectance spectra exhibitany one or more of: R400-max is greater than R500-max, R400-max isgreater than R640-max, R400-min is less than R500-min; R600-min is lessthan R500-min. In some embodiments, the reflectance spectra exhibits anyone or more of R400-max in the range from about 0.6% to about 1.5%,R400-min is in the range from about 0% to about 0.3%, R500-max is in therange of from about 0.5% to about 0.9%, R500-min is in the range fromabout 0.3% to about 0.7%, R640-max is in the range from about 0.5% toabout 0.9% and R640-min is in the range from about 0 to 0.3%.

Substrate

The substrate 110 may include an inorganic material and may include anamorphous substrate, a crystalline substrate or a combination thereof.The substrate 110 may be formed from man-made materials and/or naturallyoccurring materials (e.g., quartz and polymers). For example, in someinstances, the substrate 110 may be characterized as organic and mayspecifically be polymeric. Examples of suitable polymers include,without limitation: thermoplastics including polystyrene (PS) (includingstyrene copolymers and blends), polycarbonate (PC) (including copolymersand blends), polyesters (including copolymers and blends, includingpolyethyleneterephthalate and polyethyleneterephthalate copolymers),polyolefins (PO) and cyclicpolyolefins (cyclic-PO), polyvinylchloride(PVC), acrylic polymers including polymethyl methacrylate (PMMA)(including copolymers and blends), thermoplastic urethanes (TPU),polyetherimide (PEI) and blends of these polymers with each other. Otherexemplary polymers include epoxy, styrenic, phenolic, melamine, andsilicone resins.

In some specific embodiments, the substrate 110 may specifically excludepolymeric, plastic and/or metal substrates. The substrate may becharacterized as alkali-including substrates (i.e., the substrateincludes one or more alkalis). In one or more embodiments, the substrateexhibits a refractive index in the range from about 1.45 to about 1.55.In specific embodiments, the substrate 110 may exhibit an averagestrain-to-failure at a surface on one or more opposing major surfacethat is 0.5% or greater, 0.6% or greater, 0.7% or greater, 0.8% orgreater, 0.9% or greater, 1% or greater, 1.1% or greater, 1.2% orgreater, 1.3% or greater, 1.4% or greater 1.5% or greater or even 2% orgreater, as measured using ball-on-ring testing using at least 5, atleast 10, at least 15, or at least 20 samples. In specific embodiments,the substrate 110 may exhibit an average strain-to-failure at itssurface on one or more opposing major surface of about 1.2%, about 1.4%,about 1.6%, about 1.8%, about 2.2%, about 2.4%, about 2.6%, about 2.8%,or about 3% or greater.

Suitable substrates 110 may exhibit an elastic modulus (or Young'smodulus) in the range from about 30 GPa to about 120 GPa. In someinstances, the elastic modulus of the substrate may be in the range fromabout 30 GPa to about 110 GPa, from about 30 GPa to about 100 GPa, fromabout 30 GPa to about 90 GPa, from about 30 GPa to about 80 GPa, fromabout 30 GPa to about 70 GPa, from about 40 GPa to about 120 GPa, fromabout 50 GPa to about 120 GPa, from about 60 GPa to about 120 GPa, fromabout 70 GPa to about 120 GPa, and all ranges and sub-rangestherebetween.

In one or more embodiments, the amorphous substrate may include glass,which may be strengthened or non-strengthened. Examples of suitableglass include soda lime glass, alkali aluminosilicate glass, alkalicontaining borosilicate glass and alkali aluminoborosilicate glass. Insome variants, the glass may be free of lithia. In one or morealternative embodiments, the substrate 110 may include crystallinesubstrates such as glass ceramic substrates (which may be strengthenedor non-strengthened) or may include a single crystal structure, such assapphire. In one or more specific embodiments, the substrate 110includes an amorphous base (e.g., glass) and a crystalline cladding(e.g., sapphire layer, a polycrystalline alumina layer and/or or aspinel (MgAl₂O₄) layer).

The substrate 110 may be substantially planar or sheet-like, althoughother embodiments may utilize a curved or otherwise shaped or sculptedsubstrate. The substrate 110 may be substantially optically clear,transparent and free from light scattering. In such embodiments, thesubstrate may exhibit an average light transmission over the opticalwavelength regime of about 85% or greater, about 86% or greater, about87% or greater, about 88% or greater, about 89% or greater, about 90% orgreater, about 91% or greater or about 92% or greater. In one or morealternative embodiments, the substrate 110 may be opaque or exhibit anaverage light transmission over the optical wavelength regime of lessthan about 10%, less than about 9%, less than about 8%, less than about7%, less than about 6%, less than about 5%, less than about 4%, lessthan about 3%, less than about 2%, less than about 1%, or less thanabout 0%. In some embodiments, these light reflectance and transmittancevalues may be a total reflectance or total transmittance (taking intoaccount reflectance or transmittance on both major surfaces of thesubstrate) or may be observed on a single side of the substrate (i.e.,on the anti-reflective surface 122 only, without taking into account theopposite surface). Unless otherwise specified, the average reflectanceor transmittance is measured at an incident illumination angle of 0degrees (however, such measurements may be provided at incidentillumination angles of 45 degrees or 60 degrees). The substrate 110 mayoptionally exhibit a color, such as white, black, red, blue, green,yellow, orange etc.

Additionally or alternatively, the physical thickness of the substrate110 may vary along one or more of its dimensions for aesthetic and/orfunctional reasons. For example, the edges of the substrate 110 may bethicker as compared to more central regions of the substrate 110. Thelength, width and physical thickness dimensions of the substrate 110 mayalso vary according to the application or use of the article 100.

The substrate 110 may be provided using a variety of differentprocesses. For instance, where the substrate 110 includes an amorphoussubstrate such as glass, various forming methods can include float glassprocesses and down-draw processes such as fusion draw and slot draw.

Once formed, a substrate 110 may be strengthened to form a strengthenedsubstrate. As used herein, the term “strengthened substrate” may referto a substrate that has been chemically strengthened, for examplethrough ion-exchange of larger ions for smaller ions in the surface ofthe substrate. However, other strengthening methods known in the art,such as thermal tempering, or utilizing a mismatch of the coefficient ofthermal expansion between portions of the substrate to createcompressive stress and central tension regions, may be utilized to formstrengthened substrates.

Where the substrate is chemically strengthened by an ion exchangeprocess, the ions in the surface layer of the substrate are replacedby—or exchanged with—larger ions having the same valence or oxidationstate. Ion exchange processes are typically carried out by immersing asubstrate in a molten salt bath containing the larger ions to beexchanged with the smaller ions in the substrate. It will be appreciatedby those skilled in the art that parameters for the ion exchangeprocess, including, but not limited to, bath composition andtemperature, immersion time, the number of immersions of the substratein a salt bath (or baths), use of multiple salt baths, additional stepssuch as annealing, washing, and the like, are generally determined bythe composition of the substrate and the desired compressive stress(CS), depth of compressive stress layer (or depth of layer) of thesubstrate that result from the strengthening operation. By way ofexample, ion exchange of alkali metal-containing glass substrates may beachieved by immersion in at least one molten bath containing a salt suchas, but not limited to, nitrates, sulfates, and chlorides of the largeralkali metal ion. The temperature of the molten salt bath typically isin a range from about 380° C. up to about 450° C., while immersion timesrange from about 15 minutes up to about 40 hours. However, temperaturesand immersion times different from those described above may also beused.

In addition, non-limiting examples of ion exchange processes in whichglass substrates are immersed in multiple ion exchange baths, withwashing and/or annealing steps between immersions, are described in U.S.patent application Ser. No. 12/500,650, filed Jul. 10, 2009, by DouglasC. Allan et al., entitled “Glass with Compressive Surface for ConsumerApplications” and claiming priority from U.S. Provisional PatentApplication No. 61/079,995, filed Jul. 11, 2008, in which glasssubstrates are strengthened by immersion in multiple, successive, ionexchange treatments in salt baths of different concentrations; and U.S.Pat. No. 8,312,739, by Christopher M. Lee et al., issued on Nov. 20,2012, and entitled “Dual Stage Ion Exchange for Chemical Strengtheningof Glass,” and claiming priority from U.S. Provisional PatentApplication No. 61/084,398, filed Jul. 29, 2008, in which glasssubstrates are strengthened by ion exchange in a first bath is dilutedwith an effluent ion, followed by immersion in a second bath having asmaller concentration of the effluent ion than the first bath. Thecontents of U.S. patent application Ser. No. 12/500,650 and U.S. Pat.No. 8,312,739 are incorporated herein by reference in their entirety.

The degree of chemical strengthening achieved by ion exchange may bequantified based on the parameters of central tension (CT), surface CS,and depth of layer (DOL). Surface CS may be measured near the surface orwithin the strengthened glass at various depths. A maximum CS value mayinclude the measured CS at the surface (CS_(s)) of the strengthenedsubstrate. The CT, which is computed for the inner region adjacent thecompressive stress layer within a glass substrate, can be calculatedfrom the CS, the physical thickness t, and the DOL. CS and DOL aremeasured using those means known in the art. Such means include, but arenot limited to, measurement of surface stress (FSM) using commerciallyavailable instruments such as the FSM-6000, manufactured by Luceo Co.,Ltd. (Tokyo, Japan), or the like, and methods of measuring CS and DOLare described in ASTM 1422C-99, entitled “Standard Specification forChemically Strengthened Flat Glass,” and ASTM 1279.19779 “Standard TestMethod for Non-Destructive Photoelastic Measurement of Edge and SurfaceStresses in Annealed, Heat-Strengthened, and Fully-Tempered Flat Glass,”the contents of which are incorporated herein by reference in theirentirety. Surface stress measurements rely upon the accurate measurementof the stress optical coefficient (SOC), which is related to thebirefringence of the glass substrate. SOC in turn is measured by thosemethods that are known in the art, such as fiber and four point bendmethods, both of which are described in ASTM standard C770-98 (2008),entitled “Standard Test Method for Measurement of Glass Stress-OpticalCoefficient,” the contents of which are incorporated herein by referencein their entirety, and a bulk cylinder method. The relationship betweenCS and CT is given by the expression (1):

CT=(CS˜DOL)/(t−2DOL)  (1),

wherein t is the physical thickness (μm) of the glass article. Invarious sections of the disclosure, CT and CS are expressed herein inmegaPascals (MPa), physical thickness t is expressed in eithermicrometers (μm) or millimeters (mm) and DOL is expressed in micrometers(μm).

In one embodiment, a strengthened substrate 110 can have a surface CS of250 MPa or greater, 300 MPa or greater, e.g., 400 MPa or greater, 450MPa or greater, 500 MPa or greater, 550 MPa or greater, 600 MPa orgreater, 650 MPa or greater, 700 MPa or greater, 750 MPa or greater or800 MPa or greater. The strengthened substrate may have a DOL of 10 μmor greater, 15 μm or greater, 20 μm or greater (e.g., 25 μm, 30 μm, 35μm, 40 μm, 45 μm, 50 μm or greater) and/or a CT of 10 MPa or greater, 20MPa or greater, 30 MPa or greater, 40 MPa or greater (e.g., 42 MPa, 45MPa, or 50 MPa or greater) but less than 100 MPa (e.g., 95, 90, 85, 80,75, 70, 65, 60, 55 MPa or less). In one or more specific embodiments,the strengthened substrate has one or more of the following: a surfaceCS greater than 500 MPa, a DOL greater than 15 μm, and a CT greater than18 MPa.

Example glasses that may be used in the substrate may include alkalialuminosilicate glass compositions or alkali aluminoborosilicate glasscompositions, though other glass compositions are contemplated. Suchglass compositions are capable of being chemically strengthened by anion exchange process. One example glass composition comprises SiO₂, B₂O₃and Na₂O, where (SiO₂+B₂O₃)≧66 mol. %, and Na₂O≧9 mol. %. In anembodiment, the glass composition includes at least 6 wt. % aluminumoxide. In a further embodiment, the substrate includes a glasscomposition with one or more alkaline earth oxides, such that a contentof alkaline earth oxides is at least 5 wt. %. Suitable glasscompositions, in some embodiments, further comprise at least one of K₂O,MgO, and CaO. In a particular embodiment, the glass compositions used inthe substrate can comprise 61-75 mol. % SiO2; 7-15 mol. % Al₂O₃; 0-12mol. % B₂O₃; 9-21 mol. % Na₂O; 0-4 mol. % K₂O; 0-7 mol. % MgO; and 0-3mol. % CaO.

A further example glass composition suitable for the substratecomprises: 60-70 mol. % SiO₂; 6-14 mol. % Al₂O₃; 0-15 mol. % B₂O₃; 0-15mol. % Li₂O; 0-20 mol. % Na₂O; 0-10 mol. % K₂O; 0-8 mol. % MgO; 0-10mol. % CaO; 0-5 mol. % ZrO₂; 0-1 mol. % SiO₂; 0-1 mol. % CeO₂; less than50 ppm As₂O₃; and less than 50 ppm Sb₂O₃; where 12 mol.%≦(Li₂O+Na₂O+K₂O)≦20 mol. % and 0 mol. %≦(MgO+CaO)≦10 mol. %.

A still further example glass composition suitable for the substratecomprises: 63.5-66.5 mol. % SiO₂; 8-12 mol. % Al₂O₃; 0-3 mol. % B₂O₃;0-5 mol. % Li₂O; 8-18 mol. % Na₂O; 0-5 mol. % K₂O; 1-7 mol. % MgO; 0-2.5mol. % CaO; 0-3 mol. % ZrO₂; 0.05-0.25 mol. % SiO₂; 0.05-0.5 mol. %CeO₂; less than 50 ppm As₂O₃; and less than 50 ppm Sb₂O₃; where 14 mol.%≦(Li₂O+Na₂O+K₂O) 18 mol. % and 2 mol. %≦(MgO+CaO)≦7 mol. %.

In a particular embodiment, an alkali aluminosilicate glass compositionsuitable for the substrate comprises alumina, at least one alkali metaland, in some embodiments, greater than 50 mol. % SiO₂, in otherembodiments at least 58 mol. % SiO₂, and in still other embodiments atleast 60 mol. % SiO₂, wherein the ratio (Al₂O₃+B₂O₃)/Σ modifiers (i.e.,sum of modifiers) is greater than 1, where in the ratio the componentsare expressed in mol. % and the modifiers are alkali metal oxides. Thisglass composition, in particular embodiments, comprises: 58-72 mol. %SiO₂; 9-17 mol. % Al₂O₃; 2-12 mol. % B₂O₃; 8-16 mol. % Na₂O; and 0-4mol. % K₂O, wherein the ratio (Al₂O₃+B₂O₃)/Σ modifiers (i.e., sum ofmodifiers) is greater than 1.

In still another embodiment, the substrate may include an alkalialuminosilicate glass composition comprising: 64-68 mol. % SiO₂; 12-16mol. % Na₂O; 8-12 mol. % Al₂O₃; 0-3 mol. % B₂O₃; 2-5 mol. % K₂O; 4-6mol. % MgO; and 0-5 mol. % CaO, wherein: 66 mol. %≦SiO₂+B₂O₃+CaO≦69 mol.%; Na₂O+K₂O+B₂O₃+MgO+CaO+SrO>10 mol. %; 5 mol. %≦MgO+CaO+SrO≦8 mol. %;(Na₂O+B₂O₃)−Al₂O₃≦2 mol. %; 2 mol. %≦Na₂O−Al₂O₃≦6 mol. %; and 4 mol.%≦(Na₂O+K₂O)−Al₂O₃≦10 mol. %.

In an alternative embodiment, the substrate may comprise an alkalialuminosilicate glass composition comprising: 2 mol % or more of Al₂O₃and/or ZrO₂, or 4 mol % or more of Al₂O₃ and/or ZrO₂.

Where the substrate 110 includes a crystalline substrate, the substratemay include a single crystal, which may include Al₂O₃. Such singlecrystal substrates are referred to as sapphire. Other suitable materialsfor a crystalline substrate include polycrystalline alumina layer and/orspinel (MgAl₂O₄).

Optionally, the crystalline substrate 110 may include a glass ceramicsubstrate, which may be strengthened or non-strengthened. Examples ofsuitable glass ceramics may include Li₂O—Al₂O₃—SiO₂ system (i.e.LAS-System) glass ceramics, MgO—Al₂O₃—SiO₂ system (i.e. MAS-System)glass ceramics, and/or glass ceramics that include a predominant crystalphase including β-quartz solid solution, β-spodumene ss, cordierite, andlithium disilicate. The glass ceramic substrates may be strengthenedusing the chemical strengthening processes disclosed herein. In one ormore embodiments, MAS-System glass ceramic substrates may bestrengthened in Li₂SO₄ molten salt, whereby an exchange of 2Li⁺ for Mg²⁺can occur.

The substrate 110 according to one or more embodiments can have aphysical thickness ranging from about 100 μm to about 5 mm. Examplesubstrate 110 physical thicknesses range from about 100 μm to about 500μm (e.g., 100, 200, 300, 400 or 500 μm). Further example substrate 110physical thicknesses range from about 500 μm to about 1000 μm (e.g.,500, 600, 700, 800, 900 or 1000 μm). The substrate 110 may have aphysical thickness greater than about 1 mm (e.g., about 2, 3, 4, or 5mm) In one or more specific embodiments, the substrate 110 may have aphysical thickness of 2 mm or less or less than 1 mm. The substrate 110may be acid polished or otherwise treated to remove or reduce the effectof surface flaws.

Anti-Reflective Coating

As shown in FIG. 1, the anti-reflective coating 120 may include aplurality of layers 120A, 120B, 120C. In some embodiments, one or morelayers may be disposed on the opposite side of the substrate 110 fromthe anti-reflective coating 120 (i.e., on major surface 114)(not shown).

The physical thickness of the anti-reflective coating 120 may be in therange from about 0.1 μm to about 1 μm. In some instances, the physicalthickness of the anti-reflective coating 120 may be in the range fromabout 0.01 μm to about 0.9 μm, from about 0.01 μm to about 0.8 μm, fromabout 0.01 μm to about 0.7 μm, from about 0.01 μm to about 0.6 μm, fromabout 0.01 μm to about 0.5 μm, from about 0.01 μm to about 0.4 μm, fromabout 0.01 μm to about 0.3 μm, from about 0.01 μm to about 0.2 μm, fromabout 0.01 μm to about 0.1 μm, from about 0.02 μm to about 1 μm, fromabout 0.03 μm to about 1 μm, from about 0.04 μm to about 1 μm, fromabout 0.05 μm to about 1 μm, from about 0.06 μm to about 1 μm, fromabout 0.07 μm to about 1 μm, from about 0.08 μm to about 1 μm, fromabout 0.09 μm to about 1 μm, from about 0.2 μm to about 1 μm, from about0.3 μm to about 1 μm, from about 0.4 μm to about 1 μm, from about 0.5 μmto about 1 μm, from about 0.6 μm to about 1 μm, from about 0.7 μm toabout 1 μm, from about 0.8 μm to about 1 μm, or from about 0.9 μm toabout 1 μm, and all ranges and sub-ranges therebetween.

In one or more embodiments, the anti-reflective coating 120 may includea period 130 comprising two or more layers. In one or more embodiments,the two or more layers may be characterized as having differentrefractive indices from each another. In one embodiment, the period 130includes a first low RI layer 130A and a second high RI layer 130B. Thedifference in the refractive index of the first low RI layer and thesecond high RI layer may be about 0.01 or greater, 0.05 or greater, 0.1or greater or even 0.2 or greater.

As shown in FIG. 2, the anti-reflective coating 120 may include aplurality of periods (130). A single period includes include a first lowRI layer 130A and a second high RI layer 130B, such that when aplurality of periods are provided, the first low RI layer 130A(designated for illustration as “L”) and the second high RI layer 130B(designated for illustration as “H”) alternate in the following sequenceof layers: L/H/L/H or H/L/H/L, such that the first low RI layer and thesecond high RI layer appear to alternate along the physical thickness ofthe anti-reflective coating 120. In the example in FIG. 2, theanti-reflective coating 120 includes three periods. In some embodiments,the anti-reflective coating 120 may include up to 25 periods. Forexample, the anti-reflective coating 120 may include from about 2 toabout 20 periods, from about 2 to about 15 periods, from about 2 toabout 10 periods, from about 2 to about 12 periods, from about 3 toabout 8 periods, from about 3 to about 6 periods.

In the embodiment shown in FIG. 2, the anti-reflective coating 120 mayinclude an additional capping layer 131, which may include a lowerrefractive index material than the second high RI layer 130B.

In some embodiments, the period 130 may include one or more third layers130C, as shown in FIG. 3. The third layer(s) 130C may have a low RI, ahigh RI or a medium RI. In some embodiments, the third layer(s) 130C mayhave the same RI as the first low RI layer 130A or the second high RIlayer 130B. In other embodiments, the third layer(s) 130C may have amedium RI that is between the RI of the first low RI layer 130A and theRI of the second high RI layer 130B. Alternatively, the third layer(s)130C may have a refractive index greater than the 2^(nd) high RI layer130B. The third layer may be provided in the anti-reflective coating 120in the following exemplary configurations: L_(third layer)/H/L/H/L;H_(third layer)/L/H/L/H; L/H/L/H/L_(third layer);H/L/H/L/H_(third layer); L_(third layer)/H/L/H/L/H_(third layer);H_(third layer)/L/H/L/H/L_(third layer); L_(third layer)/L/H/L/H;H_(third layer)/H/L/H/L; H/L/H/L/L_(third layer);L/H/L/H/H_(third layer); L_(third layer)/L/H/L/H/H_(third layer);H_(third layer)/H/L/H/L/L_(third layer); L/M_(third layer)/H/L/M/H;H/M/L/H/M/L; M/L/H/L/M; and other combinations. In these configurations,“L” without any subscript refers to the first low RI layer and “H”without any subscript refers to the second high RI layer. Reference to“L_(third sub-layer)” refers to a third layer having a low RI,“H_(third sub-layer)” refers to a third layer having a high RI and “M”refers to a third layer having a medium RI, all relative to the 1^(st)layer and the 2^(nd) layer.

As used herein, the terms “low RI”, “high RI” and “medium RI” refer tothe relative values for the RI to another (e.g., low RI<medium RI<highRI). In one or more embodiments, the term “low RI” when used with thefirst low RI layer or with the third layer, includes a range from about1.3 to about 1.7. In one or more embodiments, the term “high RI” whenused with the second high RI layer or with the third layer, includes arange from about 1.6 to about 2.5. In some embodiments, the term “mediumRI” when used with the third layer, includes a range from about 1.55 toabout 1.8. In some instances, the ranges for low RI, high RI and mediumRI may overlap; however, in most instances, the layers of theanti-reflective coating 120 have the general relationship regarding RIof: low RI<medium RI<high RI.

The third layer(s) 130C may be provided as a separate layer from aperiod 130 and may be disposed between the period or plurality ofperiods and an additional coating 140 instead of the capping 131 or inaddition to the capping layer 131, as shown in FIG. 4. The thirdlayer(s) may also be provided as a separate layer from a period 130 andmay have disposed between the substrate 110 and the plurality of periods130, as shown in FIG. 5.

Exemplary materials suitable for use in the anti-reflective coating 120include: SiO₂, Al₂O₃, GeO₂, SiO, AlOxNy, AlN, SiNx, SiO_(x)N_(y),Si_(u)Al_(v)O_(x)N_(y), Ta₂O₅, Nb₂O₅, TiO₂, ZrO₂, TiN, MgO, MgF₂, BaF₂,CaF₂, SnO₂, HfO₂, Y₂O₃, MoO₃, DyF₃, YbF₃, YF₃, CeF₃, polymers,fluoropolymers, plasma-polymerized polymers, siloxane polymers,silsesquioxanes, polyimides, fluorinated polyimides, polyetherimide,polyethersulfone, polyphenylsulfone, polycarbonate, polyethyleneterephthalate, polyethylene naphthalate, acrylic polymers, urethanepolymers, polymethylmethacrylate, other materials cited below assuitable for use in a scratch-resistant layer, and other materials knownin the art. Some examples of suitable materials for use in the first lowRI layer include SiO₂, Al₂O₃, GeO₂, SiO, AlO_(x)N_(y), SiO_(x)N_(y),Si_(n)Al_(v)O_(x)N_(y), MgO, MgAl₂O₄, MgF₂, BaF₂, CaF₂, DyF₃, YbF₃, YF₃,and CeF₃. The nitrogen content of the materials for use in the first lowRI layer may be minimized (e.g., in materials such as Al₂O₃ andMgAl₂O₄). Some examples of suitable materials for use in the second highRI layer include Si_(u)Al_(v)O_(x)N_(y), Ta₂O₅, Nb₂O₅, AlN, Si₃N₄,AlO_(x)N_(y), SiO_(x)N_(y), HfO₂, TiO₂, ZrO₂, Y₂O₃, Al₂O₃, MoO₃ anddiamond-like carbon. The oxygen content of the materials for the secondhigh RI layer may be minimized, especially in SiNx or AlNx materials.The foregoing materials may be hydrogenated up to about 30% by weight.Where a material having a medium refractive index is desired, someembodiments may utilize AlN and/or SiO_(x)N_(y). The hardness of thesecond high RI layer may be characterized specifically. In someembodiments, the hardness, as measured by the Berkovitch IndenterHardness Test may be about 8 GPa or greater, about 10 GPa or greater,about 12 GPa or greater, about 15 GPa or greater, about 18 GPa orgreater, or about 20 GPa or greater. In some cases, the second high RIlayer material may be deposited as a single layer (i.e. not as part ofan anti-reflective coating), and this single layer may have a thicknessbetween about 500 and 2000 nm for repeatable hardness determination.

In one or more embodiments at least one of the layer(s) of theanti-reflective coating 120 may include a specific optical thicknessrange. As used herein, the term “optical thickness” is determined by(n*d), where “n” refers to the RI of the sub-layer and “d” refers to thephysical thickness of the layer. In one or more embodiments, at leastone of the layers of the anti-reflective coating 120 may include anoptical thickness in the range from about 2 nm to about 200 nm, fromabout 10 nm to about 100 nm, or from about 15 nm to about 100 nm. Insome embodiments, all of the layers in the anti-reflective coating 120may each have an optical thickness in the range from about 2 nm to about200 nm, from about 10 nm to about 100 nm or from about 15 nm to about100 nm. In some cases, at least one layer of the anti-reflective coating120 has an optical thickness of about 50 nm or greater. In some cases,each of the first low RI layers have an optical thickness in the rangefrom about 2 nm to about 200 nm, from about 10 nm to about 100 nm, orfrom about 15 nm to about 100 nm. In other cases, each of the secondhigh RI layers have an optical thickness in the range from about 2 nm toabout 200 nm, from about 10 nm to about 100 nm, or from about 15 nm toabout 100 nm. In yet other cases, each of the third layers have anoptical thickness in the range from about 2 nm to about 200 nm, fromabout 10 nm to about 100 nm, or from about 15 nm to about 100 nm.

In some embodiments, the thickness of one or more of the layers of theanti-reflective coating 120 may be minimized. In one or moreembodiments, the thickness of the thickness of the high RI layer(s)and/or the medium RI layer(s) are minimized such that they are less thanabout 500 nm. In one or more embodiments, the combined thickness of thehigh RI layer(s), the medium RI (layers) and/or the combination of thehigh RI and medium RI layers is less than about 500 nm.

In one or more embodiments, the anti-reflective coating 120 has aphysical thickness of about 800 nm or less. The anti-reflective coating120 may have a physical thickness in the range from about 10 nm to about800 nm, from about 50 nm to about 800 nm, from about 100 nm to about 800nm, from about 150 nm to about 800 nm, from about 200 nm to about 800nm, from about 10 nm to about 750 nm, from about 10 nm to about 700 nm,from about 10 nm to about 650 nm, from about 10 nm to about 600 nm, fromabout 10 nm to about 550 nm, from about 10 nm to about 500 nm, fromabout 10 nm to about 450 nm, from about 10 nm to about 400 nm, fromabout 10 nm to about 350 nm, from about 10 nm to about 300 nm, fromabout 50 to about 300, and all ranges and sub-ranges therebetween.

In one or more embodiments, the combined physical thickness of thesecond high RI layer(s) may be characterized. For example, in someembodiments, the combined thickness of the second high RI layer(s) maybe about 100 nm or greater, about 150 nm or greater, about 200 nm orgreater, about 500 nm or greater. The combined thickness is thecalculated combination of the thicknesses of the individual high RIlayer(s) in the anti-reflective coating 120, even when there areintervening low RI layer(s) or other layer(s). In some embodiments, thecombined physical thickness of the second high RI layer(s), which mayalso comprise a high-hardness material (e.g., a nitride or anoxynitride), may be greater than 30% of the total physical thickness ofthe anti-reflective coating. For example, the combined physicalthickness of the second high RI layer(s) may be about 40% or greater,about 50% or greater, about 60% or greater, about 70% or greater, about75% or greater, or even about 80% or greater, of the total physicalthickness of the anti-reflective coating.

In some embodiments, greater proportions of hard and high-index materialwithin the anti-reflective coating can also simultaneously be made toalso exhibit low reflectance, low color, and high abrasion resistance asfurther described elsewhere herein.

In some embodiments, the anti-reflective coating 120 exhibits an averagelight reflectance of about 2% or less, 1.5% or less, 0.75% or less, 0.5%or less, 0.25% or less, 0.1% or less, or even 0.05% or less over theoptical wavelength regime, when measured at the anti-reflective surface122 (e.g., when removing the reflections from an uncoated back surface(e.g., 114 in FIG. 1) of the article, such as through usingindex-matching oils on the back surface coupled to an absorber, or otherknown methods). In some instances, the anti-reflective coating 120 mayexhibit such average light reflectance over other wavelength ranges suchas from about 450 nm to about 650 nm, from about 420 nm to about 680 nm,from about 420 nm to about 700 nm, from about 420 nm to about 740 nm,from about 420 nm to about 850 nm, or from about 420 nm to about 950 nm.In some embodiments, the anti-reflective surface 122 exhibits an averagelight transmission of about 90% or greater, 92% or greater, 94% orgreater, 96% or greater, or 98% or greater, over the optical wavelengthregime. Unless otherwise specified, the average reflectance ortransmittance is measured at an incident illumination angle of 0 degrees(however, such measurements may be provided at incident illuminationangles of 45 degrees or 60 degrees).

The article 100 may include one or more additional coatings 140 disposedon the anti-reflective coating, as shown in FIG. 6. In one or moreembodiments, the additional coating may include an easy-to-cleancoating. An example of a suitable an easy-to-clean coating is describedin U.S. patent application Ser. No. 13/690,904, entitled “PROCESS FORMAKING OF GLASS ARTICLES WITH OPTICAL AND EASY-TO-CLEAN COATINGS,” filedon Nov. 30, 2012, which is incorporated herein in its entirety byreference. The easy-to-clean coating may have a thickness in the rangefrom about 5 nm to about 50 nm and may include known materials such asfluorinated silanes. In some embodiments, the easy-to-clean coating mayhave a thickness in the range from about 1 nm to about 40 nm, from about1 nm to about 30 nm, from about 1 nm to about 25 nm, from about 1 nm toabout 20 nm, from about 1 nm to about 15 nm, from about 1 nm to about 10nm, from about 5 nm to about 50 nm, from about 10 nm to about 50 nm,from about 15 nm to about 50 nm, from about 7 nm to about 20 nm, fromabout 7 nm to about 15 nm, from about 7 nm to about 12 nm or from about7 nm to about 10 nm, and all ranges and sub-ranges therebetween.

The additional coating 140 may include a scratch resistant coating. Ascratch resistant coating may also be included in one of the layers ofthe anti-reflective coating 120. Exemplary materials used in the scratchresistant coating may include an inorganic carbide, nitride, oxide,diamond-like material, or combination of these. Examples of suitablematerials for the scratch resistant coating include metal oxides, metalnitrides, metal oxynitride, metal carbides, metal oxycarbides, and/orcombinations thereof combination thereof. Exemplary metals include B,Al, Si, Ti, V, Cr, Y, Zr, Nb, Mo, Sn, Hf, Ta and W. Specific examples ofmaterials that may be utilized in the scratch resistant coating mayinclude Al₂O₃, AlN, AlO_(x)N_(y), Si₃N₄, SiO_(x)N_(y),Si_(u)Al_(v)O_(x)N_(y), diamond, diamond-like carbon, Si_(x)C_(y),Si_(x)O_(y)C_(z), ZrO₂, TiO_(x)N_(y) and combinations thereof.

In some embodiments, the additional coating 140 includes a combinationof easy-to-clean material and scratch resistant material. In oneexample, the combination includes an easy-to-clean material anddiamond-like carbon. Such additional coatings 140 may have a thicknessin the range from about 5 nm to about 20 nm. The constituents of theadditional coating 140 may be provided in separate layers. For example,the diamond-like carbon may be disposed as a first layer and the easy-toclean can be disposed as a second layer on the first layer ofdiamond-like carbon. The thicknesses of the first layer and the secondlayer may be in the ranges provided above for the additional coating.For example, the first layer of diamond-like carbon may have a thicknessof about 1 nm to about 20 nm or from about 4 nm to about 15 nm (or morespecifically about 10 nm) and the second layer of easy-to-clean may havea thickness of about 1 nm to about 10 nm (or more specifically about 6nm). The diamond-like coating may include tetrahedral amorphous carbon(Ta—C), Ta—C:H, and/or a-C—H.

A second aspect of this disclosure pertains to a method for forming thearticles described herein. In one embodiment, the method includesproviding a substrate having a major surface in a coating chamber,forming a vacuum in the coating chamber, forming a durableanti-reflective coating having a thickness of about 1 μm or less on themajor surface, optionally forming an additional coating comprising atleast one of an easy-to-clean coating and a scratch resistant coating,on the anti-reflective coating, and removing the substrate from thecoating chamber. In one or more embodiments, the anti-reflective coatingand the additional coating are formed in either the same coating chamberor without breaking vacuum in separate coating chambers.

In one or more embodiments, the method may include loading the substrateon carriers which are then used to move the substrate in and out ofdifferent coating chambers, under load lock conditions so that a vacuumis preserved as the substrate is moved.

The anti-reflective coating 120 and/or the additional coating 140 may beformed using various deposition methods such as vacuum depositiontechniques, for example, chemical vapor deposition (e.g., plasmaenhanced chemical vapor deposition (PECVD), low-pressure chemical vapordeposition, atmospheric pressure chemical vapor deposition, andplasma-enhanced atmospheric pressure chemical vapor deposition),physical vapor deposition (e.g., reactive or nonreactive sputtering orlaser ablation), thermal or e-beam evaporation and/or atomic layerdeposition. Liquid-based methods may also be used such as spraying orslot coating. Where vacuum deposition is utilized, inline processes maybe used to form the anti-reflective coating 120 and/or the additionalcoating 140 in one deposition run. In some instances, the vacuumdeposition can be made by a linear PECVD source.

In some embodiments, the method may include controlling the thickness ofthe anti-reflective coating 120 and/or the additional coating 140 sothat it does not vary by more than about 4% along at least about 80% ofthe area of the anti-reflective surface 122 or from the target thicknessfor each layer at any point along the substrate area. In someembodiments, the thickness of the anti-reflective layer coating 120and/or the additional coating 140 so that it does not vary by more thanabout 4% along at least about 95% of the area of the anti-reflectivesurface 122.

EXAMPLES

Various embodiments will be further clarified by the following examples.In the Examples, it should be noted that AlOxNy and SiuAlvOxNy werefound to be substantially interchangeable as the high-index material inthe modeled examples, with only minor process adjustments necessary tore-create the targeted refractive index dispersion values and layerthickness designs provided, which are apparent to one of ordinary skillin the art.

Example 1

Example 1 was formed by providing a glass substrate having a nominalcomposition of 69 mol % SiO₂, 10 mol % Al₂O₃, 15 mol % Na₂O, and 5 mol %MgO and disposing an anti-reflective coating having five layers on theglass substrate, as shown in Table 1 and in FIG. 7 using aplasma-enhanced chemical vapor deposition (PECVD) process.

TABLE 1 Anti-reflective coating attributes for Example 1. LayerReference No. Material Thickness Ambient medium — Air — Third layer131   SiN_(x)  9.55 nm 1^(st) Period 1^(st) low RI layer 130B SiO₂ 64.34nm 2^(nd) high RI layer 130A SiN_(x) 51.20 nm 2^(nd) Period 1^(st) lowRI layer 130B SiO₂ 28.89 nm 2^(nd) high RI layer 130A SiN_(x) 24.10 nmSubstrate 110  Glass

The refractive index of the second high RI layers was in the range fromabout 1.6 to about 2.1 depending on the amount of nitrogen present inthose layers. The resulting article was transparent and exhibitedabrasion resistance after 2000 cycles of linear abrasion test.

FIG. 8 shows the reflectance spectrum for Example 1 over the opticalwavelength regime. Example 1 exhibited a reflectance of less than about0.5% along a portion of the optical wavelength regime and a reflectanceof about 2% or less over the entire optical wavelength regime.

Modeled Example 2

Modeled Example 2 was prepared using the same glass substrate as used inExample 1, as shown in Table 2.

TABLE 2 Anti-reflective coating and easy-to-clean coating attributes forModeled Example 2. Layer Material Thickness Refractive Index Ambientmedium Air 1 Additional coating easy-to- 10 nm 1.407 clean 1^(st) Period1^(st) low RI layer SiO₂ 84 nm 1.463 2^(nd) high RI layer SiN_(x) 52 nm2.113 2^(nd) Period 1^(st) low RI layer SiO₂ 15 nm 1.463 2^(nd) high RIlayer SiN_(x) 47 nm 2.113 3^(rd) Period 1^(st) low RI layer SiO₂ 41 nm1.463 2^(nd) high RI layer SiN_(x) 13 nm 2.113 Substrate Glass 1.523

The reflectance of Modeled Example 2 was simulated as shown in FIG. 9(the thicknesses shown are not exact and intended to be illustrative).As shown in FIG. 9, the reflectance of Modeled Example 2 was less thanabout 0.5% over the wavelength ranges from about 420 nm to about 620 nmand was less than 1% over the entire optical wavelength regime.

It should be noted that Modeled Example 2 may be modified to includethicker or thinner additional coatings of easy-to-clean (e.g., fromabout 7 nm to about 15 nm), having a refractive index in the range fromabout 1.2 to about 1.5, depending on the materials selected and theformation process utilized.

Modeled Example 3

Modeled Example 3 was prepared using the same glass substrate as used inExample 1 and included an anti-reflective coating, a DLC coating havinga thickness of 6 nm or 10 nm disposed on the anti-reflective coating,and an easy-to-clean coating on the DLC coating as shown in Table 3.

TABLE 3 Anti-reflective coating, easy-to-clean coating and DLC coatingattributes for Modeled Example 3. Layer Material Thickness RefractiveIndex Ambient medium Air 1 Additional coating Easy-to- 1.407 cleanAdditional coating DLC 6 nm or 2.137 10 nm 1^(st) Period 1^(st) low RIlayer SiO₂ 1.463 2^(nd) high RI layer TiO₂ 2.457 2^(nd) Period 1^(st)low RI layer SiO₂ 1.463 2^(nd) high RI layer TiO₂ 2.457 3^(rd) Period1^(st) low RI layer SiO₂ 1.463 2^(nd) high RI layer TiO₂ 2.457 SubstrateGlass 1.523

The reflectance of Modeled Example 3 was simulated for the different DLCcoating thicknesses, and is shown together in FIG. 10. As shown in FIG.10, the reflectance of Modeled Example 3 for both DLC coatingthicknesses were both less than about 1% over the optical wavelengthregime. In the embodiment where the DLC coating was about 6 nm, thereflectance was even lower (i.e., less than about 0.5%) over the entireoptical wavelength regime. For clarity, the reflectance spectrum forModeled Example 3 with the DLC coating having a thickness of 6 nm isshown in FIG. 11.

Modeled Examples 4-8

Examples 4-8 used modeling to understand the reflectance spectra ofarticles that included embodiments of a durable anti-reflective coating,as described herein. In Modeled Examples 4-8, Si_(n)Al_(v)O_(x)N_(y) andSiO₂ layers, and a strengthened aluminosilicate glass substrate having anominal composition of about 58 mol % SiO₂, 17 mol % Al₂O₃, 17 mol %Na₂O, 3 mol % MgO, 0.1 mol % SnO, and 6.5 mol % P₂O₅ were used.

To determine the refractive index dispersion curves for the coatingmaterials, layers of each coating material were formed onto siliconwafers by DC, RF or RF superimposed DC reactive sputtering from asilicon, aluminum, silicon and aluminum combined or co-sputtered, ormagnesium fluoride target (respectively) at a temperature of about 50°C. using ion assist. The wafer was heated to 200° C. during depositionof some layers and targets having a 3 inch diameter were used. Reactivegases used included nitrogen, fluorine and oxygen; argon was used as theinert gas. The RF power was supplied to the silicon target at 13.56 Mhzand DC power was supplied to the Si target, Al target and other targets.

The refractive indices (as a function of wavelength) of each of theformed layers and the glass substrate were measured using spectroscopicellipsometry. The refractive indices thus measured were then used tocalculate reflectance spectra for Modeled Examples 4-8. The modeledexamples use a single refractive index value in their descriptive tablesfor convenience, which corresponds to a point selected from thedispersion curves at about 550 nm wavelength.

Example 4 included a 6-layer anti-reflective coating, including layers210, 220, 230, 240, 250 and 260 sequentially disposed on top of oneanother, disposed on a strengthened aluminosilicate glass substrate 200as shown in FIG. 12 (the thicknesses shown are not exact and intended tobe illustrative) and in Table 7.

TABLE 7 Attributes for Modeled Example 4. Peri- Refractive ModeledPhysical Layer ods Material Index Thickness Ambient — Air 1 medium Anti-1 SiO₂-a (260) 1.4826 90 nm reflective Si_(u)Al_(v)O_(x)N_(y) (250)2.015 80 nm Coating 2 SiO₂-a (240) 1.4826 12 nm Si_(u)Al_(v)O_(x)N_(y)(230) 2.015 40 nm 3 SiO₂-a (220) 1.4826 46 nm Si_(u)Al_(v)O_(x)N_(y)(210) 2.015 10 nm Substrate — AS Glass 1.51005 — Total Coating 278 nmThickness

The total thickness of the Si_(n)Al_(v)O_(x)N_(y) layers, which have ahigher hardness as measured by the Berkovitch Indenter Hardness Test, ascompared to the SiO₂ layers, is 130 nm, which comprises about 47% of theentire thickness of the coating. Anti-reflective coatings having astructure similar to the anti-reflective coating of Modeled Example 4were fabricated by DC/RF sputtering. These coatings were found toexhibit an abrasion resistance similar to or better than the bare glasssubstrate and substantially improved abrasion resistance overconvention, oxide-only anti-reflective coatings, as illustrated byExample 15. The article according to Example 4 exhibited an abrasionsimilar to the abrasion of the bare glass substrate (without ananti-reflective coating disposed thereon).

The reflectance of a single side of the article of Example 4 wascalculated at different viewing incident illumination angles or angle ofillumination (“AOI”) and the resulting reflectance spectra is shown inFIG. 13. The reflected color, based on a 10° observer under a D65illuminant and a F2 illuminant was also measured and the a* and b*values are plotted as the incident illumination angle or AOI changedfrom 0 degrees to about 60 degrees from normal incidence at regularincrements. The plot showing the reflected color is shown in FIG. 14.

Example 5 included a 9-layer anti-reflective coating, including layers310 (third layer), 320, 330, 340, 350, 360, 370, 380, and 390sequentially disposed on top of one another, disposed on a strengthenedaluminosilicate glass substrate 200, as shown in FIG. 15 (thethicknesses shown in FIG. 15 are not exact and intended to beillustrative) and the relative thicknesses of the layers are shown inTable 8.

TABLE 8 Attributes for Modeled Example 5. Peri- Refractive ModeledPhysical Layer ods Material Index Thickness Ambient — Air 1 medium Anti-1 SiO₂-a (390) 1.4826 88 nm reflective Si_(u)Al_(v)O_(x)N_(y) (380)2.015 81 nm coating 2 SiO₂-a (370) 1.4826 29 nm Si_(u)Al_(v)O_(x)N_(y)(360) 2.015 22 nm 3 SiO₂-a (350) 1.4826 120 nm Si_(u)Al_(v)O_(x)N_(y)(340) 2.015 14 nm 4 SiO₂-a (330) 1.4826 68 nm Si_(u)Al_(v)O_(x)N_(y)(320) 2.015 16 nm — SiO₂-a (310) 1.4826 26 nm Substrate — AS Glass1.51005 — Total Coating 464 nm Thickness

In Modeled Example 5, the total thickness of the Si_(u)Al_(v)O_(x)N_(y)layers, which have a higher hardness as measured by the BerkovitchIndenter Hardness Test as compared to the SiO₂ layers, is 133 nm, whichcomprises about 29% of the entire thickness of the coating. The articleaccording to Example 5 is believed to exhibit an abrasion similar to theabrasion of the bare glass substrate (without an anti-reflective coatingdisposed thereon).

The reflectance of a single side of the article of Example 5 wascalculated at different viewing incident illumination angles or angle ofillumination (“AOI”) and the resulting reflectance spectra is shown inFIG. 16. The reflected color, based on a 10° observer under a D65illuminant was also measured and the a* and b* values are plotted as theincident illumination angle or AOI changed from 0 degrees to about 60degrees from normal incidence at regular increments. The plot showingthe reflected color is shown in FIG. 17.

Example 6 included a 10-layer anti-reflective coating, including layers400, 410, 420, 430, 440, 450, 460, 470, 480, and 490 sequentiallydisposed on top of one another, disposed on a strengthenedaluminosilicate glass substrate 200, as shown in FIG. 18 (thethicknesses shown in FIG. 18 are not exact and intended to beillustrative) and Table 9.

TABLE 9 Attributes for Modeled Example 16. Peri- Refractive ModeledPhysical Layer ods Material Index Thickness Ambient — Air 1 medium Anti-1 SiO₂-a (490) 1.4826 86 nm reflective Si_(u)Al_(v)O_(x)N_(y) (480)2.015 152 nm coating 2 SiO₂-a (470) 1.4826 7 nm Si_(u)Al_(v)O_(x)N_(y)(460) 2.015 350 nm (but variable in the range from about 100 nm to about2000 nm) 3 SiO₂-a (450) 1.4826 9 nm Si_(u)Al_(v)O_(x)N_(y) (440) 2.01543 nm 4 SiO₂-a (430) 1.4826 31 nm Si_(u)Al_(v)O_(x)N_(y) (420) 2.015 25nm 5 SiO₂-a (410) 1.4826 53 nm Si_(u)Al_(v)O_(x)N_(y) (400) 2.015 8 nmSubstrate — AS Glass 1.51005 — Total Coating 764 nm Thickness

Layers 470, 480 and 490 are impedance matched to air and layers 400,410, 420, 430, 440 and 450 are impedance matched to the glass substrate.Accordingly, layer 460 may be modified to have a thickness in the rangefrom about 0 mm to about 500 nm or from about 100 nm to about 2000 nm,without influencing the optical properties of the anti-reflectivecoating or the article.

In Modeled Example 6, the total thickness of the Si_(u)Al_(v)O_(x)N_(y)layers, which have a higher hardness as measured by the BerkovitchIndenter Hardness Test as compared to the SiO₂ layers, is 578 nm, whichcomprises about 76% of the entire thickness of the coating.Anti-reflective coatings having a structure very similar to ModeledExample 6 were fabricated by DC/RF sputtering, and exhibited an abrasionresistance substantially better than the bare glass substrate, andsubstantially better abrasion resistance than conventional oxide-onlyanti-reflective coatings.

The reflectance of a single side of the article of Example 6 wascalculated at different viewing incident illumination angles or angle ofillumination (“AOI”) and the resulting reflectance spectra is shown inFIG. 19. The reflected color, based on a 10° observer under a D65illuminant and a F2 illuminant was also measured and the a* and b*values are plotted as the incident illumination angle or AOI changedfrom 0 degrees to about 60 degrees from normal incidence at regularincrements. The plot showing the reflected color is shown in FIG. 20.

Modeled Example 7 included a 12-layer anti-reflective coating, includinglayers 500, 505, 510, 515, 520, 530, 540, 550, 560, 570, 580, and 590sequentially disposed on top of one another, disposed on a strengthenedaluminosilicate glass substrate 200, as shown in FIG. 21 (thethicknesses shown in FIG. 21 are not exact and intended to beillustrative) and in Table 10.

TABLE 10 Attributes for Modeled Example 7. Peri- Refractive ModeledPhysical Layer ods Material Index Thickness Ambient — Air 1 medium Anti-1 SiO₂-a (590) 1.4826 87 nm reflective Si_(u)Al_(v)O_(x)N_(y) (580)2.015 148 nm coating 2 SiO₂-a (570) 1.4826 19 nm Si_(u)Al_(v)O_(x)N_(y)(560) 2.015 49 nm 3 SiO₂-a (550) 1.4826 11 nm Si_(u)Al_(v)O_(x)N_(y)(540) 2.015 500 nm (but variable in the range from about 100 nm to about5000 nm) 4 SiO₂-a (530) 1.4826 10 nm Si_(u)Al_(v)O_(x)N_(y) (520) 2.01544 nm 5 SiO₂-a (515) 1.4826 32 nm Si_(u)Al_(v)O_(x)N_(y) (510) 2.015 25nm 6 SiO₂-a (505) 1.4826 56 nm Si_(u)Al_(v)O_(x)N_(y) (500) 2.015 8 nmSubstrate — AS Glass 1.51005 — Total Coating 989 nm Thickness

Layers 550, 560, 570, 580, and 590 are impedance matched to air andlayers and 500, 505, 510, 515, 520 and 530 are impedance matched to theglass substrate. Accordingly, layer 540 may be modified to have athickness in the range from about 0 mm to about 5000 nm or from about100 nm to about 2500 nm, without influencing the optical properties ofthe anti-reflective coating or the article.

In Modeled Example 7, the total thickness of the Si_(n)Al_(v)O_(x)N_(y)layers, which have a higher hardness as measured by the BerkovitchIndenter Hardness Test as compared to the SiO₂ layers, is 774 nm, whichcomprises about 78% of the entire thickness of the coating.Anti-reflective coatings having a structure very similar to ModeledExample 7 were fabricated by DC/RF sputtering, and exhibited an abrasionresistance substantially better than the bare glass substrate, andsubstantially better abrasion resistance than conventional oxide-onlyanti-reflective coatings, as illustrated by Example 16 below.

The reflectance of a single side of the article of Example 7 wascalculated at different viewing incident illumination angles or angle ofillumination (“AOI”) and the resulting reflectance spectra is shown inFIG. 22. The reflected color, based on a 10° observer under a D65illuminant and a F2 illuminant was also measured and the a* and b*values are plotted as the incident illumination angle or AOI changedfrom 0 degrees to about 60 degrees from normal incidence at regularincrements. The plot showing the reflected color is shown in FIG. 23.

Example 8 included a 14-layer anti-reflective coating, including layers600, 605, 610, 615, 620, 625, 630, 635, 640, 650, 660, 670, 680, and 690sequentially disposed on top of one another, disposed on a strengthenedaluminosilicate glass substrate 200, as shown in FIG. 24 (thethicknesses shown in FIG. 24 are not exact and intended to beillustrative) and the relative thicknesses of the layers are shown inTable 11.

TABLE 11 Attributes for Modeled Example 8. Peri- Refractive ModeledPhysical Layer ods Material Index Thickness Ambient — Air 1 medium Anti-1 SiO₂-a (690) 1.4826 87 nm reflective Si_(u)Al_(v)O_(x)N_(y) (680)2.015 251 nm coating 2 SiO₂-a (670) 1.4826 27 nm Si_(u)Al_(v)O_(x)N_(y)(660) 2.015 11 nm 3 SiO₂-a (650) 1.4826 149 nm Si_(u)Al_(v)O_(x)N_(y)(640) 2.015 28 nm 4 SiO₂-a (635) 1.4826 17 nm Si_(u)Al_(v)O_(x)N_(y)(630) 2.015 217 nm 5 SiO₂-a (625) 1.4826 22 nm Si_(u)Al_(v)O_(x)N_(y)(620) 2.015 42 nm 6 SiO₂-a (615) 1.4826 31 nm SiuAlvOxNy 2.015 156 nm(610) 7 SiO₂-a (605) 1.4826 38 nm Si_(u)Al_(v)O_(x)N_(y) (600) 2.015 17nm Substrate — AS Glass 1.51005 — Total Coating 1093 nm Thickness

The total thickness of the Si_(u)Al_(v)O_(x)N_(y) layers, which have ahigher hardness as measured by the Berkovitch Indenter Hardness Test ascompared to the SiO₂ layers, is 722 nm, which comprises about 66% of theentire thickness of the coating

The reflectance of a single side of the article of Example 8 wascalculated at different viewing incident illumination angles or angle ofillumination (“AOI”) and the resulting reflectance spectra is shown inFIG. 25. The reflected color, based on a 10° observer under a D65illuminant and a F2 illuminant was also measured and the a* and b*values are plotted as the incident illumination angle or AOI changedfrom 0 degrees to about 60 degrees from normal incidence at regularincrements. The plot showing the reflected color is shown in FIG. 26.

Modeled Examples 9, 10A & 10B

Modeled Examples 9, 10A and 10B used the refractive indices anddispersion curves used for Modeled Examples 4-8, and shown above inTables 4-5 to calculate reflectance spectra of various anti-reflectivecoating 120 designs.

Modeled Example 9 included a 6-layer anti-reflective coatingsequentially disposed on top of one another, disposed on a strengthenedaluminosilicate glass substrate 200. The relative thicknesses of thelayers are shown in Table 12.

TABLE 12 Attributes for Modeled Example 9. Peri- Refractive ModeledPhysical Layer ods Material Index Thickness Ambient — Air 1 medium Anti-1 SiO₂-a 1.4826 95 nm reflective Si_(u)Al_(v)O_(x)N_(y) 2.015 167 nmcoating 2 SiO₂-a 1.4826 31 nm Si_(u)Al_(v)O_(x)N_(y) 2.015 37 nm 3SiO₂-a 1.4826 57 nm Si_(u)Al_(v)O_(x)N_(y) 2.015 14 nm Substrate — ASGlass 1.51005

The reflectance of a single side of the article of Modeled Example 9 wascalculated at different viewing incident illumination angles or angle ofillumination (“AOI”) and the resulting reflectance spectra is shown inFIG. 27. The reflected color, based on a 10° observer under a D65illuminant and a F2 illuminant was also measured and the a* and b*values are plotted as the incident illumination angle or AOI changedfrom 0 degrees to about 60 degrees from normal incidence at regularincrements. The plot showing the reflected color is shown in FIG. 28.

Modeled Examples 10A and 10B each included an 8-layer anti-reflectivecoating. Each layer of the coating was sequentially disposed on top ofone another, and disposed on a strengthened aluminosilicate glasssubstrate 200. The relative thicknesses of the layers are shown in Table13.

TABLE 13 Attributes for Modeled Examples 10A and 10B. Peri- RefractiveModeled Physical Layer ods Material Index Thicknesses Ambient — Air 110A 10B medium Anti- 1 SiO₂-a 1.4826 107 nm 106 nm reflectiveSi_(u)Al_(v)O_(x)N_(y) 2.015 44 nm 42 nm coating 2 SiO₂-a 1.4826 10 nm12 nm Si_(u)Al_(v)O_(x)N_(y) 2.015 86 nm 84 nm 3 SiO₂-a 1.4826 26 nm 27nm Si_(u)Al_(v)O_(x)N_(y) 2.015 27 nm 26 nm 4 SiO₂-a 1.4826 47 nm 48 nmSi_(u)Al_(v)O_(x)N_(y) 2.015 9 nm 7 nm Substrate — AS Glass 1.51005

The reflectance values of a single side of the article of Example 10Aand Example 10B were calculated at different viewing incidentillumination angles or angle of illumination (“AOI”) and the resultingreflectance spectra is shown in FIGS. 29 and 30, respectively. Thereflected color, based on a 10° observer under a D65 illuminant and a F2illuminant was also measured and the a* and b* values are plotted as theincident illumination angle or AOI changed from 0 degrees to about 60degrees from normal incidence at regular increments. The plots showingthe reflected color for Examples 10A and 10B is shown in FIGS. 31-32,respectively.

The optical performance of Modeled Examples 4, 7, 9, 10A and 10B wascompared to Modeled Comparative Example 11, which included a 6-layeranti-reflective coating of alternating Nb₂O₅ and SiO₂ layers and ahydrophobic coating disposed on the anti-reflective coating. To generateModeled Comparative Example 11, ion-assisted e-beam deposition was usedto deposit a single layer of Nb₂O₅ onto a silicon wafer and a singlelayer of SiO₂ onto a silicon wafer. The refractive indices as a functionof wavelength for these layers were measured using spectroscopicellipsometry. The measured refractive indices were then used in ModeledComparative Example 11. The optical performance evaluated includesaverage reflectance over the wavelength range from about 450 nm to about650 nm and color shift (with reference to a* and b* coordinates (−1,−1), using the equation √(a*_(example)−(−1))²+(b*_(example)−(−1))²))when viewed at an incident illumination angles in the range from about 0degrees to about 60 degrees from normal incidence under F02 and D65illuminants. Table 14 shows the average reflectance and the greatestcolor shift of Modeled Examples 4, 7, 9, 10A and 10B and ModeledComparative Example 11.

TABLE 14 Average Reflectance and Color Shift for Modeled Examples 4, 7,9, 10A and 10B and Modeled Comparative Example 11. Avg. Reflec- ColorShift Refer- tance 450-650 enced to (a*, b*) = Ex. nm (%) (−1, −1)Modeled Example 4, 6-layer 0.5 4.0 Si_(u)Al_(v)O_(x)N_(y) orAlO_(x)N_(y)/SiO₂ Modeled Example 7, 12-layer 1.0 2.5Si_(u)Al_(v)O_(x)N_(y) or AlO_(x)N_(y)/SiO₂ Modeled Example 9, 6-layer0.8 3.6 Si_(u)Al_(v)O_(x)N_(y) or AlO_(x)N_(y)/SiO₂ Modeled Example 10A,8-layer 1.5 1.2 Si_(u)Al_(v)O_(x)N_(y) or AlO_(x)N_(y)/SiO₂ ModeledExample 10B, 8-layer 2.0 0.6 Si_(u)Al_(v)O_(x)N_(y) or AlO_(x)N_(y)/SiO₂Modeled Comp. Ex. 11, 6-layer 0.3 7.9 Nb2O5/SiO2/hydrophobic coating

As shown in Table 14, while Modeled Comparative 11 exhibited the lowestaverage reflectance, it also exhibited the greatest color shift. ModeledExample 4 exhibited comparable reflectance and a significantly reducedcolor shift. Modeled Examples 7, 9, 10A and 10B had even less colorshift though, reflectance was increased slightly.

Examples 12-18

Examples 12-18 included either bare aluminosilicate glass substrates(with no coatings) or aluminosilicate glass substrates with variousanti-reflective or hard coatings as shown in Table 15. Thealuminosilicate glass substrates were chemically strengthened andexhibited a compressive stress in the range from about 700 MPa to about900 MPa and depths of compressive stress layer values in the range fromabout 40 μm to about 50 μm. The anti-reflective coatings were depositedusing reactive DC sputtering, e-beam evaporation, and reactive DC and RFsputtering. The anti-reflective coatings included layers of SiO₂,Si_(n)Al_(v)O_(x)N_(y), AlO_(x)N_(y), and Nb₂O₅. SiO₂ layers were formedby either DC reactive sputtering from a Si target at about 200° C. withion assist or by ion-assisted e-beam deposition, as indicated in Table15. Nb₂O₅ layers were deposited by ion-assisted e-beam deposition.Layers of Si_(n)Al_(v)O_(x)N_(y) were deposited by DC reactivesputtering combined with RF superimposed DC sputtering using a substrateheated to 200° C. substrate heating with ion assist.Si_(n)Al_(v)O_(x)N_(y) layers were made by reactive sputtering in anAJA-Industries Sputter Deposition Tool. The targets used to form theSi_(u)Al_(v)O_(x)N_(y) layers were 3″ diameter Si and 3″ diameter Al.The reactive gasses were nitrogen and oxygen, and the “working” (orinert) gas was Argon. The power supplied to the Si target was radiofrequency (RF) at 13.56 Mhz. The power supplied to the Al target was DC.It should be noted that layers of AlOxNy could be substituted for thelayers of Si_(n)Al_(v)O_(x)N_(y) layers and can be formed using the sameor similar process used to form such layers. BothSi_(n)Al_(v)O_(x)N_(y), and AlOxNy layers can be made to exhibit arefractive index at 550 nm of about 1.95 and a measured hardness greaterthan 15 GPa measured using the Berkovitch Indenter Hardness Test.

TABLE 15 Anti-reflective coating structures for Examples 12-18. ExampleCoating Structure Ex. 12 6-layers, having the same structure andmaterials as modeled Ex. 4 Ex. 13 12-layers, having the same structureand materials as modeled Example 7 Comparative 6L having the samestructure and materials as Modeled Ex. 14 Comparative Example 11Comparative chemically strengthened glass with hydrophobic Ex. 15coating only Comprative single layer of Si_(u)Al_(v)O_(x)N_(y) having athickness of 186 nm Ex. 16 Comparative single layer ofSi_(u)Al_(v)O_(x)N_(y) having a thickness of 478 nm Ex. 17 Comparativechemically strengthened glass with no coatings (bare) Ex. 18

Table 16 shows the abrasion resistance of Examples 12-13 and ComparativeExamples 14-18, as measured in terms of measured scattered lightintensity (CCBTDF, 1/steradian) and transmission haze (with 8 mmaperture) after subjecting the samples to the Taber Test. The averagereflectance was measured at the anti-reflective surface without abrasion(single surface measurement, subtracting out 4% reflectance from theopposite, uncoated surface).

TABLE 16 Average Reflectance (without abrasion) and abrasion resistance,as measured by scattered light intensity and transmission haze (afterbeing subjected to the Taber Test) for Examples 12-13 and ComparativeExamples 14-18. Range of Avg. Scattered light intensity - TransmissionReflectance Avg. +/− Std. Dev. Haze (Non-abraded) (CCBTDF, 1/steradian)With 7 mm 450-650 Example At 20 degrees At 40 degrees aperture nm (%)Ex. 12 0.012 +/− 0.004 0.004 +/− 0.002 0.1-0.2 0.7 Ex. 13 0.008 +/−0.006 0.002 +/− 0.001 0   0.7 Comparative 0.13 +/− 0.04 0.09 +/− 0.031.3-2.8 0.5 Ex. 14 Comparative 0.022 +/− 0.015 0.008 +/− 0.004 0.25-0.354.0 Ex. 15 Comparative 0.03 +/− 0.01 0.008 +/− 0.006 0.8 8.4 Ex. 16Comparative 0.018 +/− 0.001 0.008 +/− 0.002 0.3 6.0 Ex. 17 Comparative0.021 +/− 0.004 0.007 +/− 0.003 0.1-0.4 4.0 Ex. 18 Comparative 0.002 +/−0.001  0.001 +/− 0.0004   0-0.2 4.0 Ex. 18(Without Abrading)

As shown in Table 16, Examples 12 and 13 approached the scattered lightintensity of the Comparative Ex. 18 without abrading (or without beingsubjected to the Taber Test) at 40 degrees, indicating superior abrasionresistance. Examples 12 and 13 also exhibited the least scattered lightintensity at 20 degrees, of all the samples after being subjected to theTaber Test. The transmission haze of both Examples 12 and 13 wassubstantially the same as the transmission haze for Comparative Ex. 18without abrading. The average reflectance of Examples 12 and 13 wassignificantly improved over Comparative Example 18, with onlyComparative Example 14 exhibiting less average reflectance.

FIG. 33 is a graph shows the scattered light intensity (CCBTDF,1/steradian) measurements of Table 16, along polar angles orthogonal toabrasion direction for Examples 12-13 and Comparative Examples 15-17,with and without being subjected to the Taber Test. Lower scatteringintensity values indicate less severe abrasion and thus greater abrasionresistance (and lower abrasion visibility in human inspection trials).

The abrasion resistance of Examples 12-13 and Comparative Examples 14,17-18 was evaluated by AFM roughness, after being subjected to the TaberTest. Table 17 shows AFM roughness statistics (average and std. dev.)reported for 5 scans of an 80×80 micron area within the abraded region.As shown in Table 17, Examples 12 and 13 exhibited very low roughness,as compared to Comparative Ex. 14 and 18. Comparative Ex. 17 exhibitedlow roughness but also exhibited relatively high reflectance and lightscattering, as shown above in Table 17.

TABLE 17 Abrasion resistance, as measured by AFM roughness statistics,after being subjected to the Taber Test, for Examples 12-13 andComparative Examples 14, 17 and 18. AFM roughness (Ra, Std. Dev. (of Ra,Examples nm, 5 scan average) nm, 5 scans) Example 12 7.1 5.4 Example 133.5 2.9 Comp. Ex. 14 16.8 8.2 Comp. Ex. 17 4.5 0.7 Comp. Ex. 18 14.1 8.9

FIG. 34 is a graph showing the AFM roughness statistics from Table 22.

Example 19

Example 19 included a 10-layer anti-reflective coating disposed on astrengthened aluminosilicate glass substrate having a nominalcomposition of about 58 mol % SiO₂, 17 mol % Al₂O₃, 17 mol % Na₂O, 3 mol% MgO, 0.1 mol % SnO, and 6.5 mol % P₂O₅. The thicknesses of the layersare shown in Table 18.

Both SiO₂ and Si_(n)Al_(v)O_(x)N_(y) layers were made by reactivesputtering in a coater made by AJA Industries. SiO₂ was deposited by DCreactive sputtering from an Si target with ion assist;Si_(n)Al_(v)O_(x)N_(y) material was deposited by DC reactive sputteringcombined with RF superimposed DC sputtering with ion assist. Thereactive gasses were nitrogen and oxygen, and the “working” (or inert)gas was Argon.

TABLE 18 Attributes for Example 19. Peri- Refractive Physical Layer odsMaterial Index Thickness (nm) Ambient — Air 1 medium Anti- 1 SiO₂1.48623 96.75 reflective Si_(u)Al_(v)O_(x)N_(y) 2.03056 68.92 coating 2SiO₂ 1.48623 24.13 Si_(u)Al_(v)O_(x)N_(y) 2.03056 36.64 3 SiO₂ 1.4862370.12 Si_(u)Al_(v)O_(x)N_(y) 2.03056 28.12 4 SiO₂ 1.48623 23.54Si_(u)Al_(v)O_(x)N_(y) 2.03056 110.49 5 SiO₂ 1.48623 31.23Si_(u)Al_(v)O_(x)N_(y) 2.03056 16.82 Substrate — AS Glass 1.511 — TotalCoating 506.75 nm Thickness

The amount of high RI material is about 51.5% and the amount of low RImaterial is about 48.5% of the anti-reflective coating. The depositionconditions are shown in Table 19. The deposition temperature was 200° C.and

TABLE 19 Deposition recipe for Example 19. Dep. Ar N2 O2 Time flow flowflow Al Al Si Si P Periods Material (seconds) (sccm) (sccm) (sccm) WrfWdc Wrf shutter (torr) 1 SiO₂ 1248 200 30 30 3.3 50 75 500 1Si_(u)Al_(v)O_(x)N_(y) 633 200 30 30 0.5 200 300 500 1 2 SiO₂ 318 200 3030 3.3 50 75 500 1 Si_(u)Al_(v)O_(x)N_(y) 235 200 30 30 0.5 200 300 5001 3 SiO₂ 1011 200 30 30 3.3 50 75 500 1 Si_(u)Al_(v)O_(x)N_(y) 179 20030 30 0.5 200 300 500 1 4 SiO₂ 305 200 30 30 3.3 50 75 500 1Si_(u)Al_(v)O_(x)N_(y) 933 200 30 30 0.5 200 300 500 1 5 SiO₂ 429 200 3030 3.3 50 75 500 1 Si_(u)Al_(v)O_(x)N_(y) 121 200 30 30 0.5 200 300 5001

The reflectance values of a single side of the article of Example 19 atdifferent viewing incident illumination angles or angle of illumination(“AOI”) were modeled using the dispersion curves obtained for each ofthe coating materials and the glass substrate. The resulting modeledreflectance spectra is shown in FIG. 35. The reflected color andtransmitted color, based on a 10° observer under a D65 illuminant and aF2 illuminant were also measured and the a* and b* values are plotted asthe incident illumination angle or AOI changed from 0 degrees to about60 degrees from normal incidence at regular increments. The plot showingboth the reflected color and transmitted color for Example 19 is shownin FIG. 36. As shown in FIG. 36 and in Table 21 below, both thereflected and transmitted color are less than 3 from a*=0 and b*=0, forincident illumination angles from 0 degrees to about 60 degrees. Example19 was evaluated for photopic reflectance at different AOI. From an AOIin the range from about 0° to about 20°, the photopic reflectance may beabout 0.4 or less.

TABLE 21 Photopic reflectance, reflectance color shift, thickness andpercentage of hard material for Example 19 and Comparative Example 11. %R (Photopic Refl. Color shift Avg., Y) 5-60 degrees Total (wavelengths(max-min, D65) thickness % Hard Ex. 450-650 nm) a* b* nm materialComparative 0.4 7.0 12.4 Example 11 Ex. 19 0.4 2.5 1.4 500 51

Example 20

Example 20 included a 10-layer anti-reflective coating disposed on astrengthened aluminosilicate glass substrate having a nominalcomposition of about 58 mol % SiO₂, 17 mol % Al₂O₃, 17 mol % Na₂O, 3 mol% MgO, 0.1 mol % SnO, and 6.5 mol % P₂O₅. The thicknesses of the layersare shown in Table 22.

The SiO₂ and Si_(n)Al_(v)O_(x)N_(y) layers were made by reactivesputtering in a coater made by Optorun Co. Ltd. SiO₂ was deposited by DCreactive sputtering from a Si target with ion assist;Si_(n)Al_(v)O_(x)N_(y) material was deposited by DC reactive sputteringcombined with RF superimposed DC sputtering with ion assist. Thereactive gasses were nitrogen and oxygen, and the “working” (or inert)gas was Argon. The deposition conditions for the SiO₂ andSi_(u)Al_(v)O_(x)N_(y) layers are provided in Table 23. Each layer wasformed at 200° C. deposition temperature and for a deposition timesufficient to form the physical thickness of each layer.

TABLE 22 Attributes for Example 20. Peri- Refractive Physical Layer odsMaterial Index Thickness (nm) — Air 1 Anti- 1 SiO₂ 1.48114 89 reflectiveSi_(u)Al_(v)O_(x)N_(y) 2.00605 87.7 coating 2 SiO₂ 1.48114 21.9Si_(u)Al_(v)O_(x)N_(y) 2.00605 27.6 3 SiO₂ 1.48114 72.9Si_(u)Al_(v)O_(x)N_(y) 2.00605 23.7 4 SiO₂ 1.48114 22.9Si_(u)Al_(v)O_(x)N_(y) 2.00605 114.9 5 SiO₂ 1.48114 30.2Si_(u)Al_(v)O_(x)N_(y) 2.00605 15.6 Substrate — AS Glass 1.50542 — TotalCoating Thickness 506.4 nm

TABLE 23 Deposition conditions for Example 20. Ar N2 O2 Flow flow flowAl Al Si Si P Layer (sccm) (sccm) (sccm) Wrf Wdc Wrf shutter (torr) BiasSiO₂ 30 30 3.3 50 75 500 1 4 0 Si_(u)Al_(v)O_(x)N_(y) 30 30 0.5 200 300500 1 2 0

Example 20 exhibited a single side average reflectance (i.e., measuredfrom the anti-reflective surface 122) over the optical wavelength regimeat incident illumination angles of 0 °, 30°, 45° and 60°, of 0.86%,1.04%, 1.6%, and 3.61%, respectively. Example 20 exhibited a single sideaverage transmittance (i.e., measured from the anti-reflective surface122) over the optical wavelength regime at incident illumination anglesof 0 °, 30 °, 45° and 60°, of 99.14%, 98.95%, 98.4%, and 96.39%,respectively.

Example 20 exhibited a total average reflectance (i.e., measured fromthe anti-reflective surface 122 and the opposite major surface 114) overthe optical wavelength regime at incident illumination angles of 0 °,30°, 45° and 60°, of 4.85%, 3.56%, 2.44%, and 3.77%, respectively.Example 20 exhibited a single side average transmittance (i.e., measuredfrom the anti-reflective surface 122) over the optical wavelength regimeat incident illumination angles of 0 °, 30 °, 45° and 60°, of 95.15%,96.44%, 97.56%, and 96.23%, respectively.

The reflectance and transmitted color coordinates for a single surface(i.e., anti-reflective surface 122) and two surfaces (i.e.,anti-reflective surface 122 and major surface 114, of FIG. 1) of Example20, under incident illumination angles or AOI from 0 degrees to 60degrees (or 75 degrees) and illuminants D65 and F2 are shown in Tables24A-24D. Single surface color coordinates were measured by eliminatingtransmission or reflectance from the major surface 114, as is known inthe art. The color shift is calculated using the following equation:√((a*₂−a*₁)²+(b*₂−b*₁)²), with a*₁, and b*₁ representing the a* and b*coordinates of the article when viewed at normal incidence (i.e., AOI=0)and a*₂, and b*₂ representing the a* and b* coordinates of the articlewhen viewed at an incident illumination angle different or away fromnormal incidence (i.e., AOI=1-60 or 1-75).

TABLE 24A One surface reflectance and transmitted color coordinates (Y,L*, a* and b*) using illuminant D65 for Example 20. Reflectance, D65Transmittance, D65 AOI Y L* a* b* AOI Y L* a* b* 0 0.5366 4.8468 −2.8959−1.6828 0 99.4622 99.7917 0.1231 0.0761 1 0.5365 4.8462 −2.8956 −1.681 199.4623 99.7917 0.1231 0.076 2 0.5363 4.8443 −2.8947 −1.6757 2 99.462599.7918 0.123 0.0758 3 0.5359 4.8412 −2.893 −1.667 3 99.4628 99.79190.123 0.0754 4 0.5355 4.8369 −2.8905 −1.6551 4 99.4633 99.7921 0.12280.0749 5 0.5349 4.8315 −2.8872 −1.6403 5 99.4639 99.7923 0.1227 0.0742 60.5342 4.8251 −2.8827 −1.6229 6 99.4646 99.7926 0.1225 0.0735 7 0.53344.8178 −2.8771 −1.6033 7 99.4654 99.7929 0.1223 0.0727 8 0.5325 4.8099−2.87 −1.582 8 99.4663 99.7933 0.122 0.0717 9 0.5315 4.8014 −2.8612−1.5596 9 99.4672 99.7936 0.1216 0.0708 10 0.5306 4.7926 −2.8506 −1.536610 99.4682 99.794 0.1211 0.0698 11 0.5296 4.7838 −2.8378 −1.5136 1199.4692 99.7944 0.1206 0.0688 12 0.5286 4.7751 −2.8227 −1.4913 1299.4701 99.7948 0.1199 0.0679 13 0.5277 4.7669 −2.8049 −1.4703 1399.4711 99.7951 0.1192 0.067 14 0.5269 4.7596 −2.7842 −1.4513 14 99.471999.7954 0.1183 0.0661 15 0.5262 4.7534 −2.7604 −1.4351 15 99.472599.7957 0.1172 0.0655 16 0.5257 4.7488 −2.7333 −1.4223 16 99.473199.7959 0.1161 0.0649 17 0.5254 4.7463 −2.7026 −1.4136 17 99.4733 99.7960.1148 0.0645 18 0.5254 4.7463 −2.6681 −1.4097 18 99.4733 99.796 0.11330.0644 19 0.5258 4.7495 −2.6297 −1.4113 19 99.473 99.7959 0.1116 0.064420 0.5266 4.7563 −2.5871 −1.4191 20 99.4722 99.7956 0.1098 0.0648 210.5278 4.7675 −2.5402 −1.4336 21 99.471 99.7951 0.1078 0.0654 22 0.52964.7839 −2.489 −1.4557 22 99.4691 99.7944 0.1056 0.0664 23 0.5321 4.8062−2.4332 −1.4858 23 99.4667 99.7934 0.1032 0.0677 24 0.5353 4.8353 −2.373−1.5245 24 99.4634 99.7922 0.1006 0.0694 25 0.5394 4.8723 −2.3081−1.5726 25 99.4593 99.7906 0.0978 0.0714 26 0.5445 4.9182 −2.2386−1.6304 26 99.4543 99.7886 0.0948 0.0739 27 0.5507 4.9742 −2.1645−1.6986 27 99.4481 99.7862 0.0917 0.0769 28 0.5581 5.0416 −2.0858−1.7777 28 99.4406 99.7833 0.0883 0.0803 29 0.567 5.122 −2.0025 −1.868229 99.4317 99.7798 0.0847 0.0842 30 0.5775 5.2169 −1.9148 −1.9705 3099.4212 99.7758 0.0809 0.0886 31 0.5899 5.3281 −1.8227 −2.0851 3199.4089 99.771 0.077 0.0935 32 0.6042 5.4577 −1.7263 −2.2123 32 99.394599.7654 0.0729 0.099 33 0.6208 5.6078 −1.6258 −2.3526 33 99.3779 99.75890.0685 0.1051 34 0.64 5.7808 −1.5214 −2.5062 34 99.3587 99.7515 0.06410.1117 35 0.662 5.9794 −1.4133 −2.6735 35 99.3367 99.743 0.0594 0.118936 0.6871 6.2066 −1.3016 −2.8546 36 99.3116 99.7332 0.0546 0.1268 370.7158 6.4657 −1.1867 −3.0459 37 99.2829 99.7221 0.0497 0.1352 38 0.74846.7603 −1.0688 −3.2299 38 99.2503 99.7094 0.0446 0.1443 39 0.7854 7.0945−0.9482 −3.3995 39 99.2133 99.695 0.0395 0.1539 40 0.8273 7.4726 −0.8253−3.548 40 99.1714 99.6787 0.0342 0.1642 41 0.8745 7.8997 −0.7003 −3.667841 99.1241 99.6603 0.0288 0.1751 42 0.9279 8.3754 −0.5592 −3.7604 4299.0708 99.6396 0.0234 0.1866 43 0.9879 8.8899 −0.4162 −3.8434 4399.0108 99.6162 0.0179 0.1988 44 1.0553 9.4441 −0.2829 −3.9167 4498.9433 99.59 0.0123 0.2115 45 1.1311 10.0387 −0.16 −3.9793 45 98.867699.5605 0.0068 0.2247 46 1.216 10.6748 −0.0477 −4.0308 46 98.782699.5274 0.0012 0.2386 47 1.3111 11.3531 0.0537 −4.0708 47 98.687599.4903 −0.0044 0.253 48 1.4176 12.0745 0.1444 −4.099 48 98.581 99.4487−0.0099 0.2679 49 1.5367 12.8397 0.2244 −4.1155 49 98.4619 99.4022−0.0154 0.2833 50 1.6699 13.6496 0.2942 −4.1202 50 98.3287 99.3501−0.0208 0.2993 51 1.8186 14.5047 0.3541 −4.1135 51 98.18 99.292 −0.02620.3157 52 1.9846 15.406 0.4047 −4.0957 52 98.014 99.227 −0.0315 0.332553 2.1698 16.3541 0.4466 −4.0673 53 97.8288 99.1543 −0.0367 0.3498 542.3764 17.3501 0.4805 −4.0288 54 97.6222 99.0732 −0.0419 0.3674 552.6068 18.3947 0.5072 −3.9809 55 97.3918 98.9826 −0.0469 0.3855 562.8635 19.4889 0.5273 −3.9242 56 97.135 98.8815 −0.0519 0.404 57 3.149720.6339 0.5416 −3.8593 57 96.8488 98.7685 −0.0568 0.4228 58 3.468621.8306 0.5508 −3.787 58 96.53 98.6424 −0.0616 0.4419 59 3.8239 23.08040.5556 −3.708 59 96.1747 98.5016 −0.0663 0.4614 60 4.2196 24.3845 0.5567−3.6229 60 95.779 98.3443 −0.071 0.4812 Reflectance color shift Low:0.0018 Transmittance color shift Low: 0.0001 range between normal High:1.97861 range from normal High: 0.4492 incidence (AOI = 0 incidence (AOI= 0) to degrees) to AOI = 36 AOI = 60 degrees Reflectance color shiftLow: 2.1861 range between normal High: 4.1114 incidence (AOI = 0degrees) and AOI = 37- 60 degrees

TABLE 24B One surface reflectance and transmitted color coordinates (Y,L*, a* and b*) using illuminant F2 for Example 20. Reflectance, F2Transmittance, F2 AOI Y L* a* b* AOI Y L* a* b* 0 0.4711 4.2557 −1.6317−1.9631 0 99.5279 99.8172 0.0693 0.0885 1 0.4711 4.2552 −1.6304 −1.96181 99.5279 99.8172 0.0692 0.0884 2 0.4709 4.2538 −1.6264 −1.9583 299.5281 99.8172 0.069 0.0883 3 0.4707 4.2515 −1.6197 −1.9524 3 99.528399.8173 0.0687 0.088 4 0.4703 4.2482 −1.6104 −1.9443 4 99.5287 99.81750.0683 0.0877 5 0.4699 4.2443 −1.5983 −1.9342 5 99.5291 99.8176 0.06780.0872 6 0.4694 4.2397 −1.5835 −1.9224 6 99.5296 99.8178 0.0672 0.0867 70.4688 4.2346 −1.5659 −1.9091 7 99.5302 99.8181 0.0664 0.0862 8 0.46824.2291 −1.5454 −1.8946 8 99.5308 99.8183 0.0656 0.0855 9 0.4676 4.2236−1.5221 −1.8792 9 99.5314 99.8185 0.0646 0.0849 10 0.467 4.2181 −1.4959−1.8633 10 99.532 99.8188 0.0634 0.0842 11 0.4664 4.213 −1.4668 −1.847211 99.5326 99.819 0.0622 0.0835 12 0.4659 4.2086 −1.4348 −1.8314 1299.5331 99.8192 0.0608 0.0828 13 0.4655 4.2051 −1.3999 −1.8161 1399.5335 99.8193 0.0593 0.0822 14 0.4653 4.2031 −1.3621 −1.8019 1499.5337 99.8194 0.0577 0.0816 15 0.4653 4.2027 −1.3216 −1.789 15 99.533799.8194 0.0559 0.081 16 0.4655 4.2046 −1.2783 −1.7778 16 99.5335 99.81930.0541 0.0805 17 0.466 4.2092 −1.2324 −1.7688 17 99.533 99.8191 0.05210.0802 18 0.4669 4.217 −1.184 −1.7622 18 99.5321 99.8188 0.05 0.0799 190.4681 4.2287 −1.1333 −1.7585 19 99.5308 99.8183 0.0479 0.0797 20 0.46994.2448 −1.0805 −1.758 20 99.529 99.8176 0.0456 0.0797 21 0.4723 4.2661−1.0257 −1.7611 21 99.5267 99.8167 0.0432 0.0799 22 0.4753 4.2934−0.9693 −1.7683 22 99.5237 99.8155 0.0408 0.0802 23 0.4791 4.3274−0.9115 −1.78 23 99.5199 99.8141 0.0383 0.0807 24 0.4837 4.3692 −0.8526−1.7966 24 99.5153 99.8123 0.0358 0.0814 25 0.4893 4.4197 −0.793 −1.818725 99.5097 99.8101 0.0332 0.0824 26 0.496 4.4801 −0.7328 −1.8468 2699.503 99.8075 0.0307 0.0836 27 0.5039 4.5514 −0.6726 −1.8817 27 99.495199.8044 0.0281 0.0851 28 0.5131 4.6352 −0.6127 −1.9239 28 99.485899.8008 0.0255 0.0869 29 0.524 4.7328 −0.5534 −1.9742 29 99.475 99.79660.023 0.0891 30 0.5365 4.8458 −0.4952 −2.0334 30 99.4625 99.7918 0.02050.0917 31 0.5509 4.976 −0.4384 −2.1023 31 99.4481 99.7862 0.018 0.094732 0.5674 5.1253 −0.3835 −2.182 32 99.4315 99.7798 0.0157 0.0981 330.5863 5.2958 −0.3307 −2.2734 33 99.4126 99.7724 0.0134 0.102 34 0.60785.4899 −0.2806 −2.3774 34 99.3911 99.7641 0.0112 0.1065 35 0.6321 5.7101−0.2335 −2.4952 35 99.3668 99.7546 0.0092 0.1116 36 0.6597 5.9593−0.1897 −2.6277 36 99.3392 99.7439 0.0073 0.1174 37 0.6909 6.2406−0.1497 −2.7761 37 99.308 99.7318 0.0056 0.1238 38 0.726 6.5575 −0.1138−2.9365 38 99.2729 99.7182 0.0041 0.131 39 0.7654 6.9139 −0.0823 −3.088639 99.2335 99.7029 0.0027 0.1389 40 0.8097 7.314 −0.0556 −3.2243 4099.1892 99.6856 0.0016 0.1477 41 0.8594 7.7626 −0.0341 −3.3366 4199.1395 99.6663 0.0006 0.1573 42 0.915 8.262 −0.0175 −3.4219 42 99.083999.6447 −0.0001 0.1678 43 0.9772 8.7997 −0.007 −3.5027 43 99.021799.6205 −0.0005 0.1793 44 1.0467 9.3743 −0.0026 −3.5818 44 98.952299.5934 −0.0007 0.1917 45 1.1243 9.9866 −0.004 −3.6584 45 98.874699.5632 −0.0006 0.2051 46 1.2109 10.6374 −0.0105 −3.7314 46 98.78899.5294 −0.0003 0.2196 47 1.3075 11.3276 −0.0214 −3.7999 47 98.691499.4918 0.0004 0.2351 48 1.4151 12.058 −0.0362 −3.863 48 98.5837 99.44980.0013 0.2517 49 1.5351 12.8295 −0.0542 −3.92 49 98.4637 99.4029 0.00250.2693 50 1.6687 13.6429 −0.0747 −3.97 50 98.3301 99.3507 0.0041 0.28851 1.8176 14.4992 −0.0972 −4.0126 51 98.1812 99.2924 0.006 0.3077 521.9833 15.3994 −0.121 −4.0471 52 98.0155 99.2275 0.0081 0.3286 53 2.167816.3444 −0.1457 −4.0733 53 97.831 99.1552 0.0106 0.3505 54 2.373217.3352 −0.1706 −4.0907 54 97.6256 99.0745 0.0135 0.3735 55 2.601918.3731 −0.1953 −4.0992 55 97.397 98.9846 0.0166 0.3976 56 2.856419.4592 −0.2193 −4.0987 56 97.1424 98.8844 0.02 0.4227 57 3.1397 20.5949−0.2424 −4.0891 57 96.8591 98.7726 0.0238 0.4488 58 3.4551 21.7814−0.264 −4.0706 58 96.5437 98.6479 0.0278 0.476 59 3.8062 23.0202 −0.2839−4.0431 59 96.1926 98.5087 0.0321 0.5041 60 4.1972 24.3129 −0.3019−4.007 60 95.8016 98.3534 0.0366 0.5332 Reflectance color shift Low:0.0018 Transmittance color shift Low: 0.0001 range between normal High:1.9150 range from normal High: 0.4459 incidence (AOI = 0 incidence (AOI= 0) to degrees) to AOI = 39 AOI = 60 degrees Reflectance color shiftLow: 2.1859 range between normal High: 2.5810 incidence (AOI = 0degrees) and AOI = 40- 60 degrees

TABLE 24C Two surface reflectance and transmitted color coordinates (Y,L*, a* and b*) using illuminant D65 for Example 20. Reflectance, D65Transmittance, D65 AOI Y L* a* b* AOI Y L* a* b* 0 4.5668 25.4632−0.9446 −1.0023 0 95.4319 98.2061 0.1224 0.1381 1 4.5668 25.463 −0.9445−1.0018 1 95.432 98.2061 0.1224 0.138 2 4.5666 25.4624 −0.9442 −1.0002 295.4322 98.2062 0.1224 0.1378 3 4.5663 25.4615 −0.9438 −0.9977 3 95.432598.2063 0.1223 0.1375 4 4.5658 25.4602 −0.943 −0.9942 4 95.4329 98.20650.1222 0.137 5 4.5653 25.4587 −0.942 −0.9898 5 95.4334 98.2067 0.12210.1364 6 4.5648 25.457 −0.9407 −0.9847 6 95.434 98.2069 0.1219 0.1357 74.5642 25.4553 −0.939 −0.9789 7 95.4345 98.2071 0.1216 0.1349 8 4.563625.4535 −0.9368 −0.9727 8 95.4351 98.2073 0.1213 0.134 9 4.5631 25.452−0.9341 −0.966 9 95.4356 98.2076 0.121 0.1331 10 4.5627 25.4508 −0.9307−0.9592 10 95.436 98.2077 0.1205 0.1322 11 4.5625 25.4501 −0.9267−0.9524 11 95.4362 98.2078 0.12 0.1313 12 4.5625 25.4501 −0.9218 −0.945712 95.4362 98.2078 0.1194 0.1304 13 4.5628 25.451 −0.9161 −0.9395 1395.4359 98.2077 0.1186 0.1295 14 4.5635 25.4532 −0.9094 −0.9337 1495.4352 98.2074 0.1178 0.1288 15 4.5647 25.4568 −0.9016 −0.9288 1595.434 98.2069 0.1168 0.1281 16 4.5665 25.4622 −0.8926 −0.9247 1695.4322 98.2062 0.1156 0.1276 17 4.569 25.4697 −0.8824 −0.9219 1795.4297 98.2052 0.1143 0.1273 18 4.5723 25.4798 −0.8708 −0.9203 1895.4264 98.2039 0.1129 0.1271 19 4.5766 25.4927 −0.8578 −0.9203 1995.4221 98.2022 0.1113 0.1272 20 4.582 25.5091 −0.8434 −0.922 20 95.416798.2 0.1095 0.1275 21 4.5887 25.5293 −0.8275 −0.9255 21 95.41 98.19730.1075 0.1282 22 4.5969 25.5539 −0.8099 −0.931 22 95.4018 98.1941 0.10530.1291 23 4.6067 25.5836 −0.7908 −0.9386 23 95.392 98.1901 0.103 0.130324 4.6184 25.6188 −0.77 −0.9484 24 95.3802 98.1855 0.1004 0.1319 254.6323 25.6605 −0.7475 −0.9606 25 95.3664 98.1799 0.0977 0.1338 264.6486 25.7092 −0.7234 −0.9751 26 95.3501 98.1734 0.0947 0.1361 274.6675 25.7658 −0.6976 −0.9922 27 95.3311 98.1659 0.0916 0.1389 284.6895 25.8313 −0.6702 −1.0117 28 95.3092 98.1571 0.0882 0.142 29 4.714925.9065 −0.6412 −1.0336 29 95.2838 98.147 0.0847 0.1456 30 4.743925.9924 −0.6106 −1.058 30 95.2547 98.1353 0.0809 0.1496 31 4.777226.0903 −0.5786 −1.0847 31 95.2215 98.1221 0.077 0.1541 32 4.815126.2013 −0.5451 −1.1137 32 95.1836 98.1069 0.0729 0.159 33 4.858126.3265 −0.5104 −1.1447 33 95.1406 98.0897 0.0686 0.1644 34 4.906826.4675 −0.4744 −1.1775 34 95.0919 98.0703 0.0641 0.1702 35 4.961826.6256 −0.4374 −1.2119 35 95.0369 98.0483 0.0595 0.1765 36 5.023826.8023 −0.3995 −1.2476 36 94.9749 98.0235 0.0547 0.1832 37 5.093426.9993 −0.3608 −1.2842 37 94.9052 97.9956 0.0498 0.1903 38 5.171627.2182 −0.3217 −1.3213 38 94.827 97.9643 0.0447 0.1979 39 5.259227.4608 −0.2821 −1.3584 39 94.7394 97.9292 0.0395 0.2058 40 5.357127.7289 −0.2424 −1.395 40 94.6415 97.8899 0.0342 0.214 41 5.4665 28.0244−0.2029 −1.4306 41 94.5321 97.846 0.0288 0.2225 42 5.5884 28.3493−0.1636 −1.4645 42 94.4102 97.797 0.0234 0.2313 43 5.7242 28.7057−0.1249 −1.4961 43 94.2744 97.7424 0.0178 0.2403 44 5.8753 29.0956−0.0869 −1.5249 44 94.1233 97.6817 0.0122 0.2494 45 6.0431 29.521−0.0499 −1.5501 45 93.9554 97.614 0.0065 0.2585 46 6.2295 29.9842−0.0142 −1.5712 46 93.7691 97.5389 0.0008 0.2676 47 6.4362 30.48720.0202 −1.5877 47 93.5624 97.4554 −0.0049 0.2767 48 6.6652 31.03220.0531 −1.5989 48 93.3334 97.3627 −0.0106 0.2855 49 6.9188 31.62130.0842 −1.6044 49 93.0798 97.26 −0.0164 0.2941 50 7.1993 32.2565 0.1136−1.6038 50 92.7992 97.146 −0.0222 0.3023 51 7.5096 32.9399 0.141 −1.596851 92.489 97.0198 −0.028 0.3101 52 7.8523 33.6733 0.1666 −1.5833 5292.1462 96.88 −0.0338 0.3174 53 8.2307 34.4588 0.1902 −1.563 53 91.767896.7253 −0.0397 0.324 54 8.6483 35.2981 0.2118 −1.5361 54 91.3502 96.554−0.0456 0.3298 55 9.1088 36.1929 0.2317 −1.5027 55 90.8897 96.3646−0.0516 0.3349 56 9.6163 37.1447 0.2497 −1.4629 56 90.3822 96.1551−0.0577 0.339 57 10.1752 38.1551 0.2659 −1.4172 57 89.8232 95.9234−0.0639 0.3422 58 10.7904 39.2253 0.2806 −1.366 58 89.208 95.6673−0.0703 0.3443 59 11.4672 40.3565 0.2937 −1.3099 59 88.5312 95.3842−0.0769 0.3453 60 12.2111 41.5497 0.3055 −1.2493 60 87.7873 95.0713−0.0837 0.3451 61 13.1957 43.0567 −0.2359 −0.5057 61 86.8042 94.65510.0663 0.1464 62 14.0946 44.3683 −0.2259 −0.4794 62 85.9053 94.27190.0669 0.146 63 15.0802 45.7439 −0.2148 −0.4519 63 84.9197 93.8485 0.0670.1451 64 16.16 47.1837 −0.2024 −0.4234 64 83.8399 93.3809 0.0667 0.143565 17.3418 48.6879 −0.1889 −0.3943 65 82.6581 92.8645 0.0658 0.1414 6618.634 50.2563 −0.1743 −0.3648 66 81.3659 92.2943 0.0644 0.1387 6720.0454 51.8886 −0.1589 −0.3353 67 79.9545 91.6644 0.0623 0.1355 6821.5851 53.584 −0.1428 −0.306 68 78.4148 90.9689 0.0595 0.1316 6923.2625 55.3417 −0.1262 −0.2772 69 76.7374 90.2006 0.056 0.1272 7025.0872 57.1602 −0.1093 −0.2493 70 74.9128 89.3521 0.0518 0.1223 7127.0688 59.038 −0.0924 −0.2223 71 72.9311 88.4148 0.0468 0.1169 7229.2172 60.9728 −0.0758 −0.1966 72 70.7827 87.3793 0.041 0.111 7331.5415 62.9622 −0.0596 −0.1722 73 68.4584 86.2351 0.0346 0.1048 7434.0508 65.0029 −0.0443 −0.1495 74 65.9491 84.9704 0.0275 0.0983 7536.7532 67.0914 −0.03 −0.1284 75 63.2467 83.572 0.0199 0.0916Reflectance color shift Low: 0.0005 Transmittance color Low: 0.0001range between normal High: 1.2800 shift range from normal High: 0.2921incidence (AOI = 0 incidence (AOI = 0) to degrees) to AOI = 75 AOI = 75degrees

TABLE 24D Two surface reflectance and transmitted color coordinates (Y,L*, a* and b*) using illuminant F2 for Example 20. Reflectance, F2Transmittance, F2 AOI Y L* a* b* AOI Y L* a* b* 0 4.4977 25.2528 −0.5382−1.1683 0 95.5013 98.2337 0.0691 0.1594 1 4.4976 25.2527 −0.5378 −1.16791 95.5013 98.2338 0.0691 0.1594 2 4.4975 25.2522 −0.5366 −1.1668 295.5015 98.2338 0.0689 0.1592 3 4.4972 25.2515 −0.5345 −1.1651 3 95.501798.2339 0.0686 0.159 4 4.4969 25.2506 −0.5316 −1.1627 4 95.502 98.2340.0682 0.1587 5 4.4966 25.2495 −0.5278 −1.1598 5 95.5024 98.2342 0.06780.1583 6 4.4962 25.2484 −0.5232 −1.1563 6 95.5027 98.2343 0.0671 0.15787 4.4958 25.2473 −0.5177 −1.1523 7 95.5031 98.2345 0.0664 0.1572 84.4955 25.2463 −0.5113 −1.148 8 95.5034 98.2346 0.0656 0.1567 9 4.495325.2457 −0.5039 −1.1435 9 95.5036 98.2347 0.0646 0.156 10 4.4953 25.2455−0.4957 −1.1387 10 95.5037 98.2347 0.0636 0.1554 11 4.4954 25.2459−0.4865 −1.1339 11 95.5035 98.2346 0.0624 0.1548 12 4.4959 25.2473−0.4764 −1.129 12 95.5031 98.2345 0.0611 0.1541 13 4.4967 25.2497−0.4653 −1.1244 13 95.5023 98.2341 0.0596 0.1535 14 4.4979 25.2536−0.4533 −1.1199 14 95.501 98.2336 0.0581 0.1529 15 4.4997 25.2591−0.4404 −1.1158 15 95.4992 98.2329 0.0564 0.1524 16 4.5022 25.2666−0.4265 −1.112 16 95.4968 98.2319 0.0547 0.152 17 4.5054 25.2765 −0.4118−1.1088 17 95.4935 98.2306 0.0528 0.1516 18 4.5095 25.2891 −0.3963−1.1062 18 95.4894 98.229 0.0508 0.1514 19 4.5147 25.3049 −0.38 −1.104319 95.4842 98.2269 0.0487 0.1512 20 4.5211 25.3243 −0.363 −1.1031 2095.4778 98.2244 0.0465 0.1512 21 4.5288 25.3479 −0.3453 −1.1028 2195.4701 98.2213 0.0443 0.1514 22 4.5382 25.3763 −0.3271 −1.1034 2295.4608 98.2176 0.042 0.1517 23 4.5492 25.4099 −0.3084 −1.1051 2395.4497 98.2132 0.0396 0.1522 24 4.5623 25.4495 −0.2893 −1.1078 2495.4366 98.2079 0.0372 0.1528 25 4.5776 25.4957 −0.27 −1.1117 25 95.421398.2018 0.0347 0.1537 26 4.5954 25.5494 −0.2505 −1.1169 26 95.403598.1947 0.0322 0.1548 27 4.616 25.6114 −0.231 −1.1235 27 95.3829 98.18650.0298 0.1562 28 4.6396 25.6824 −0.2116 −1.1315 28 95.3592 98.17710.0273 0.1579 29 4.6668 25.7636 −0.1925 −1.1411 29 95.3321 98.16620.0249 0.1598 30 4.6978 25.8558 −0.1737 −1.1524 30 95.3011 98.15390.0225 0.1621 31 4.733 25.9601 −0.1555 −1.1654 31 95.2659 98.1398 0.02010.1648 32 4.7729 26.0778 −0.1379 −1.1802 32 95.2259 98.1238 0.01790.1678 33 4.8181 26.2101 −0.1211 −1.1969 33 95.1808 98.1058 0.01570.1713 34 4.869 26.3582 −0.1052 −1.2155 34 95.1299 98.0855 0.0136 0.175235 4.9262 26.5235 −0.0903 −1.236 35 95.0726 98.0626 0.0117 0.1795 364.9905 26.7076 −0.0765 −1.2584 36 95.0084 98.0369 0.0098 0.1844 375.0624 26.9118 −0.064 −1.2826 37 94.9364 98.0081 0.0082 0.1897 38 5.142927.138 −0.0527 −1.3084 38 94.856 97.9759 0.0067 0.1956 39 5.2327 27.3877−0.0428 −1.3356 39 94.7661 97.9399 0.0053 0.2021 40 5.3328 27.6627−0.0342 −1.364 40 94.666 97.8997 0.0041 0.2091 41 5.4443 27.9649 −0.0271−1.3933 41 94.5545 97.855 0.0031 0.2166 42 5.5683 28.2961 −0.0214 −1.42342 94.4305 97.8052 0.0023 0.2246 43 5.706 28.6582 −0.0171 −1.4526 4394.2928 97.7499 0.0017 0.2332 44 5.8588 29.0534 −0.0141 −1.4817 44 94.1497.6884 0.0013 0.2423 45 6.0282 29.4836 −0.0124 −1.5097 45 93.970697.6201 0.0011 0.2518 46 6.216 29.9509 −0.0119 −1.5359 46 93.782897.5444 0.001 0.2616 47 6.4238 30.4573 −0.0124 −1.5597 47 93.575 97.46050.0012 0.2719 48 6.6536 31.0051 −0.0138 −1.5805 48 93.3451 97.36750.0015 0.2823 49 6.9078 31.5961 −0.0159 −1.5976 49 93.091 97.2645 0.00190.293 50 7.1886 32.2326 −0.0185 −1.6105 50 92.8101 97.1505 0.0024 0.303751 7.4988 32.9164 −0.0215 −1.6184 51 92.5 97.0243 0.0031 0.3145 527.8411 33.6497 −0.0247 −1.621 52 92.1577 96.8847 0.0038 0.3251 53 8.218734.4343 −0.0278 −1.6178 53 91.78 96.7303 0.0046 0.3355 54 8.6351 35.2721−0.0306 −1.6084 54 91.3636 96.5596 0.0054 0.3455 55 9.0941 36.1648−0.0329 −1.5926 55 90.9046 96.3708 0.0061 0.3551 56 9.5996 37.1141−0.0346 −1.5703 56 90.3991 96.1621 0.0068 0.364 57 10.1563 38.1215−0.0354 −1.5414 57 89.8424 95.9314 0.0073 0.3723 58 10.7689 39.1884−0.0353 −1.5062 58 89.2298 95.6764 0.0077 0.3797 59 11.4426 40.3162−0.0341 −1.4648 59 88.5561 95.3946 0.0078 0.3861 60 12.1832 41.5059−0.0318 −1.4175 60 87.8154 95.0832 0.0075 0.3915 61 13.191 43.0497−0.3225 −0.5066 61 86.8089 94.6571 0.0912 0.1466 62 14.0869 44.3573−0.3206 −0.4919 62 85.913 94.2752 0.0954 0.1498 63 15.0693 45.7289−0.316 −0.4754 63 84.9307 93.8532 0.0992 0.1525 64 16.1456 47.1649−0.309 −0.4571 64 83.8543 93.3872 0.1024 0.1548 65 17.3238 48.6655−0.2996 −0.437 65 82.6761 92.8725 0.1051 0.1566 66 18.6124 50.2306−0.288 −0.4155 66 81.3876 92.3039 0.1071 0.1577 67 20.02 51.8599 −0.2744−0.3926 67 79.9799 91.6758 0.1084 0.1583 68 21.556 53.5527 −0.259−0.3686 68 78.444 90.9821 0.1089 0.1581 69 23.2297 55.3082 −0.2422−0.3438 69 76.7702 90.2157 0.1086 0.1573 70 25.051 57.1251 −0.2243−0.3184 70 74.949 89.3691 0.1074 0.1557 71 27.0295 59.0016 −0.2055−0.2928 71 72.9705 88.4336 0.1053 0.1533 72 29.1749 60.9357 −0.1861−0.2672 72 70.825 87.3999 0.1024 0.1503 73 31.4968 62.9248 −0.1666−0.242 73 68.5031 86.2574 0.0986 0.1465 74 34.0041 64.9658 −0.1473−0.2173 74 65.9959 84.9943 0.094 0.142 75 36.7049 67.0551 −0.1284−0.1934 75 63.295 83.5974 0.0886 0.1369 Reflectance color shift Low:0.0005 Transmittance color shift Low: 0.0001 range between normal High:1.0575 range from normal High: 0.2401 incidence (AOI = 0 degrees)incidence (AOI = 0) to to AOI = 75 degrees AOI = 75

Example 21

Example 21 included a 10-layer anti-reflective coating disposed on astrengthened aluminosilicate glass substrate having a nominalcomposition of about 58 mol % SiO₂, 17 mol % Al₂O₃, 17 mol % Na₂O, 3 mol% MgO, 0.1 mol % SnO, and 6.5 mol % P₂O₅. The thicknesses of the layersare shown in Table 25.

The SiO₂ and AlO_(x)N_(y) layers were made by reactive sputtering in acoater made by Optorun Co. Ltd. SiO₂ was deposited by DC reactivesputtering from a Si target with ion assist; AlO_(x)N_(y) material wasdeposited by DC reactive sputtering combined with RF superimposed DCsputtering with ion assist. The reactive gasses were nitrogen andoxygen, and the “working” (or inert) gas was Argon. The depositionconditions for the SiO₂ and AlO_(x)N_(y) layers are provided in Table26. Each layer was formed at 200° C. deposition temperature and for adeposition time sufficient to form the physical thickness of each layer.

TABLE 25 Example 21 physical attributes. Refractive Physical LayerMaterial Index Thickness (nm) Medium Air 1 1 SiO₂ 1.47225 86.51 2 AlOxNy1.98593 93.71 3 SiO₂ 1.47225 23.29 4 AlOxNy 1.98593 26.79 5 SiO₂ 1.4722575.47 6 AlOxNy 1.98593 23.06 7 SiO₂ 1.47225 24.12 8 AlOxNy 1.98593122.78 9 SiO₂ 1.47225 33.64 10  AlOxNy 1.98593 17.32 Substrate Glass1.50542 Total coating 526.68 nm Thickness

TABLE 26 Deposition conditions for Example 21. Ar N2 O2 Flow flow flowAl Si Layer (sccm) (sccm) (sccm) Al Wrf Wdc Si Wrf shutter P (torr) BiasSiO₂ AlO_(x)N_(y)

The transmittance color coordinates at normal incidence were measuredthrough both the anti-reflective surface of Example 21 and the oppositebare surface of Example 21 using a D65 illuminant, as shown in FIG. 37and indicated by T(D65). The reflectance color coordinates were measuredon the anti-reflective surface only using a F2 illuminant and atincident illumination angles of 20 degrees, 40 degrees and 60 degreesand a reference illumination angle of 6 degrees are also plotted in FIG.37, and indicated by R(F2). The measured transmittance and reflectancecolor coordinates of the substrate are plotted in FIG. 37 and indicatedby T(glass) and R(glass), respectively. As shown in FIG. 37, thetransmittance color shift of the article with respect to thetransmittance color coordinates of the substrate is very low (i.e., lessthan about 0.5). The color shift with respect to viewing angle inreflectance between the reference illumination angle (a*=−0.53, b*=2.08)and incident viewing angles 20 degrees (a*=−0.9, b*=1.95), 40 degrees(a*=−1.7, b*=0.69) and 60 degrees (a*=−0.44, b*=−1.89) was 0.39, 1.81and 3.96, respectively.

FIG. 38 shows the reflectance spectra of Example 21 as measured on onlythe anti-reflective surface at the reference illumination angle and theincident viewing angles of 20 degrees, 40 degrees and 60 degrees. Theradiometric and photopic average of Example 21 was calculated as 0.54%.The transmittance and reflectance spectra measured at the referenceillumination angle (6 degrees) for both the anti-reflective surface andthe opposite bare surface are shown in FIG. 39.

The measured hardness and the Young's modulus of Example 21, as measuredon the anti-reflective surface, was 11.1 GPa and 110 GPa, respectively.Examples of Modeled Comparative Example 11 exhibited a hardness of about6.8 GPa.

It will be apparent to those skilled in the art that variousmodifications and variations can be made without departing from thespirit or scope of the invention.

What is claimed is:
 1. An article comprising: a substrate having a major surface; and an anti-reflective coating having a thickness of about 1 μm or less disposed on the major surface, the anti-reflective coating comprising an anti-reflective surface, wherein the article exhibits a maximum hardness of about 8 GPa or greater as measured by a Berkovich Indenter Hardness Test along an indentation depth of about 50 nm or greater; wherein the article exhibits either one or both of: a single side average light transmittance of about 94% or greater over an optical wavelength regime and a single side light reflectance of about 2% or less over the optical wavelength regime, and wherein the article exhibits a b* value, in reflectance, in the range from about −5 to about 1 as measured on the anti-reflective surface only at all incidence illumination angles in the range from about 0 degrees to about 60 degrees.
 2. The article of claim 1, wherein the b* value is measured under an F2 illuminant.
 3. The article of claim 1, wherein the article exhibits article transmittance color coordinates in the (L*, a*, b*) colorimetry system at normal incidence under an International Commission on Illumination illuminant exhibiting a reference point color shift of less than about 2 from a reference point as measured at the anti-reflective surface, the reference point comprising at least one of the color coordinates (a*=0, b*=0) and the transmittance color coordinates of the substrate, and article reflectance color coordinates in the (L*, a*, b*) colorimetry system at normal incidence under an International Commission on Illumination illuminant exhibiting a reference point color shift of less than about 5 from a reference point as measured at the anti-reflective surface, the reference point comprising at least one of the color coordinates (a*=0, b*=0), the color coordinates (a*−2, b*=−2) and the reflectance color coordinates of the substrate, wherein, when the reference point is the color coordinates (a*=0, b*=0), the color shift is defined by √((a*_(article))²+(b*_(article))²), wherein, when the reference point is the color coordinates (a*=−2, b*=−2), the color shift is defined by √(a*_(article)+2)²+(b*_(article)+2)²), and wherein, when the reference point is the color coordinates of the substrate, the color shift is defined by √((a*_(article)−a*_(substrate))²+(b*_(article)−b*_(substrate))²).
 4. The article of claim 1, wherein the article exhibits an abrasion resistance comprising about 1% haze or less, as measured using a hazemeter having an aperture, wherein the aperture has a diameter of about 8 mm, and wherein the abrasion resistance is measured after a 500-cycle abrasion using a Taber Test.
 5. The article of claim 1, wherein the article exhibits an abrasion resistance comprising an average roughness Ra, as measured by atomic force microscopy, of about 12 nm or less, and wherein the abrasion resistance is measured after a 500-cycle abrasion using a Taber Test.
 6. The article of claim 1, wherein the article exhibits an abrasion resistance comprising a scattered light intensity of about 0.05 (in units of 1/steradian) or less, at a polar scattering angle of about 40 degrees or less, as measured at normal incidence in transmission using an imaging sphere for scatter measurements, with a 2 mm aperture at 600 nm wavelength, and wherein the abrasion resistance is measured after a 500-cycle abrasion using a Taber Test.
 7. The article of claim 1, wherein the article exhibits an abrasion resistance comprising a scattered light intensity of about 0.1 (in units of 1/steradian) or less, at a polar scattering angle of about 20 degrees or less, as measured at normal incidence in transmission using an imaging sphere for scatter measurements, with a 2 mm aperture at 600 nm wavelength, and wherein the abrasion resistance is measured after a 500-cycle abrasion using a Taber Test.
 8. The article of claim 1, wherein the anti-reflective coating comprises a plurality of layers, the plurality of layers comprising a first low RI layer, a second high RI layer and an optional third layer.
 9. The article of claim 8, wherein at least one of the first low RI layer and the second high RI layer comprises an optical thickness (n*d) in the range from about 2 nm to about 200 nm.
 10. The article of claim 1, wherein the anti-reflective coating comprises a thickness of about 800 nm or less.
 11. The article of claim 1, wherein the article exhibits a reflectance angular color shift of less than about 5, as measured on the anti-reflective surface, at all angles from normal incidence to an incident illumination angle in the range from about 20 degrees to about 60 degrees under a F2 illuminant, and wherein angular color shift is calculated using the equation √(a*₂−a*₁)²+(b*₂-b*₁)²), with a*₁, and b*₁ representing the coordinates of the article when viewed at normal incidence and a*₂, and b*₂ representing the coordinates of the article when viewed at the incident illumination angle.
 12. The article of claim 1, exhibiting a reflectance spectra such that the maximum reflectance over a wavelength range from about 400 nm to about 480 nm (R400-max) is greater than the maximum reflectance over a wavelength range from about 500 nm to about 600 nm (R500-max) and the maximum reflectance over a wavelength range from about 640 nm to about 710 (R640-max), and wherein the minimum reflectance over a wavelength range from about 400 nm to about 480 nm (R400-min) is optionally less than the minimum reflectance over a wavelength range from about 500 nm to about 600 nm (R500-min), and wherein the minimum reflectance over a wavelength range from about 640 to about 710 (R640-min) is optionally less than R500-min.
 13. The article of claim 8, wherein anti-reflective coating comprises a physical thickness and a plurality of second high RI layers comprising a nitride or an oxynitride, and wherein the combined physical thickness of the second high RI layers is 40% or greater of the physical thickness of the anti-reflective coating.
 14. The article of claim 1, wherein the substrate comprises an amorphous substrate or a crystalline substrate.
 15. The article of claim 14, wherein the amorphous substrate comprises a glass selected from the group consisting of soda lime glass, alkali aluminosilicate glass, alkali containing borosilicate glass and alkali aluminoborosilicate glass.
 16. The article of claim 15, wherein the glass is chemically strengthened and comprises a compressive stress (CS) layer with a surface CS of at least 250 MPa extending within the chemically strengthened glass from a surface of the chemically strengthened glass to a depth of layer (DOL) of at least about 10 μm.
 17. The article of claim 1, further comprising any one or more of an easy-to-clean coating, a diamond-like carbon coating, and a scratch resistant coating, disposed on the anti-reflective coating.
 18. An article comprising: a substrate having a major surface; and an anti-reflective coating having a thickness of about 1 μm or less disposed on the major surface, the anti-reflective coating comprising an anti-reflective surface, wherein the article exhibits a maximum hardness of about 8 GPa or greater as measured by a Berkovich Indenter Hardness Test along an indentation depth of about 50 nm or greater; wherein the article exhibits either one or both of: a single side average light transmittance of about 94% or greater over an optical wavelength regime and a single side light reflectance of about 2% or less over the optical wavelength regime, wherein the article exhibits a reflectance angular color shift of less than about 5, as measured on the anti-reflective surface from normal incidence to an incident illumination angle in the range from about 2 degrees to about 60 degrees under a D65 illuminant or F2 illuminant, wherein angular color shift is calculated using the equation √((a*₂−a*₁)²+(b*₂−b*₁)²), with a*₁, and b*₁ representing the coordinates of the article when viewed at normal incidence and a*₂, and b*₂ representing the coordinates of the article when viewed at the incident illumination angle, and wherein the article exhibits either one or both article transmittance color coordinates in the (L*, a*, b*) colorimetry system at normal incidence the D65 or F2 illuminant exhibiting a reference point color shift of less than about 2 from a reference point as measured at the anti-reflective surface, the reference point comprising at least one of the color coordinates (a*=0, b*=0) and the transmittance color coordinates of the substrate, and article reflectance color coordinates in the (L*, a*, b*) colorimetry system at normal incidence exhibiting a color shift of less than about 5 from a reference point as measured at the anti-reflective surface, the reference point comprising at least one of the color coordinates (a*=0, b*=0), the coordinates (a*=−2, b*=−2), and the reflectance color coordinates of the substrate, wherein, when the reference point is the color coordinates (a*=0, b*=0), the color shift is defined by √(a*_(article))²+(b*_(article))²), wherein, when the reference point is the color coordinates (a*=−2, b*=−2), the color shift is defined by √(a*_(article)+2)²+(b*_(article)+2)²), and wherein, when the reference point is the color coordinates of the substrate, the color shift is defined by √(a*_(article)−a*_(substrate))²+(b*_(article)−b*_(substrate))²).
 19. The article of claim 18, wherein the article exhibits an abrasion resistance comprising any one of about 1% haze or less, as measured using a hazemeter having an aperture, wherein the aperture has a diameter of about 8 mm, an average roughness, as measured by atomic force microscopy, of about 12 nm RMS or less, a scattered light intensity of about 0.05 (in units of 1/steradian) or less, at a polar scattering angle of about 40 degrees or less, as measured at normal incidence in transmission using an imaging sphere for scatter measurements, with a 2 mm aperture at 600 nm wavelength, and a scattered light intensity of about 0.1 (in units of 1/steradian) or less, at a polar scattering angle of about 20 degrees or less, as measured at normal incidence in transmission using an imaging sphere for scatter measurements, with a 2 mm aperture at 600 nm wavelength, wherein the abrasion resistance is measured after a 500-cycle abrasion using a Taber Test.
 20. The article of claim 18, wherein the anti-reflective coating comprises a plurality of layers, the plurality of layers comprising a first low RI layer, a second high RI layer and an optional third layer, wherein at least one of the first low RI layer and the second high RI layer comprises an optical thickness (n*d) in the range from about 2 nm to about 200 nm.
 21. The article of claim 18, wherein the article exhibits the reflectance angular color shift at all angles from normal incidence to an incident illumination angle, in the range from about 20 degrees to about 60 degrees.
 22. The article of claim 18, wherein the substrate comprises an amorphous substrate or a crystalline substrate.
 23. The article of claim 18, further comprising any one or more of an easy-to-clean coating, a diamond-like carbon coating, and a scratch resistant coating, disposed on the anti-reflective coating.
 24. An article comprising: a substrate having a major surface; and an anti-reflective coating having a thickness of about 1 μm or less disposed on the major surface, wherein the article exhibits an abrasion resistance comprising any one or more of: about 1% haze or less, as measured using a hazemeter having an aperture, wherein the aperture has a diameter of about 8 mm, an average roughness, as measured by atomic force microscopy, of about 12 nm RMS or less, a scattered light intensity of about 0.05 (in units of 1/steradian) or less, at a polar scattering angle of about 40 degrees or less, as measured at normal incidence in transmission using an imaging sphere for scatter measurements, with a 2 mm aperture at 600 nm wavelength, and a scattered light intensity of about 0.1 (in units of 1/steradian) or less, at a polar scattering angle of about 20 degrees or less, as measured at normal incidence in transmission using an imaging sphere for scatter measurements, with a 2 mm aperture at 600 nm wavelength, wherein the abrasion resistance is measured after a 500-cycle abrasion using a Taber Test, wherein the article exhibits an average visible photopic reflectance of about 1% or less over the optical wavelength regime at normal incidence under a D65 or F2 illuminant, and wherein the article exhibits a b* value, in reflectance, in the range from about −5 to about 1 as measured on the anti-reflective surface only at all incidence illumination angles in the range from about 0 degrees to about 60 degrees under a D65 illuminant or F2 illuminant.
 25. The article of claim 24, wherein anti-reflective coating comprises a plurality of layers, the plurality of layers comprising at least one first low RI layer and more than one second high RI layer, and wherein the combined thickness of the second high RI layers is less than about 500 nm or less.
 26. The article of claim 24, wherein the article exhibits a single side average light transmittance of about 98% or greater over the optical wavelength regime.
 27. An article comprising: a substrate having a major surface; and an anti-reflective coating having a thickness of about 1 μm or less disposed on the major surface, wherein the article exhibits an average visible photopic reflectance of about 0.7% or less over the optical wavelength regime at normal incidence under a D65 or F2 illuminant, wherein the article exhibits a b* value, in reflectance, in the range from about −5 to about 1 as measured on the anti-reflective surface only at all incidence illumination angles in the range from about 0 degrees to about 60 degrees under a F2 illuminant, and wherein the article exhibits a reflectance angular color shift of less than about 5, as measured on the anti-reflective surface at all angles from normal incidence to an incident illumination angle in the range from about 20 degrees to about 60 degrees under a D65 illuminant or F2 illuminant and wherein angular color shift is calculated using the equation √(a*2−a*1)2+(b*2−b*1)2), with a*1, and b*1 representing the coordinates of the article when viewed at normal incidence and a*2, and b*2 representing the coordinates of the article when viewed at the incident illumination angle.
 28. The article of claim 27, wherein the article exhibits a maximum hardness of about 8 GPa or greater as measured by a Berkovich Indenter Hardness Test an indentation depth of about 50 nm or greater.
 29. The article of claim 27, wherein anti-reflective coating comprises a physical thickness and a plurality of layers comprising a nitride or oxynitride, and wherein the combined physical thickness of the layers comprising a nitride or an oxynitride is 40% or greater of the physical thickness of the anti-reflective coating.
 30. The article of claim 27, wherein the angular color shift is less than about
 2. 